Took the plunge, bought Dark Souls...

Yeah, two hits from a blowdart = instant toxin = death. That was bloody annoying. I've also discovered that the Firelink Shrine, my safe haven, is no more, the fire keeper murdered by someone and the majority of those I had gathered nearby have also gone AWOL.

Doubly annoying because I had gathered around 70,000 sould to try and up my Pyromancy skills, the last few upgrades not making a huge difference.

You can rekindle the bonfire, check the little cave where the firekeeper was, pick up the items there and hold on to the Black Eye Orb for a while, you'll figure out what you need to do after you progress a little.

If Laurentius (pyromancy guy) left Firelink you can still upgrade your flame and buy new spells from Quelana, Quelaag's sister, unless you want Iron Flesh or Flash Sweat, in which case you'll have to wait until NG+.

Iron Flesh and Flash Sweat I bought from Laurentius already, but my flame is only at +7 so plenty of room to improve. Where do I find Quelana?

She's in Blighttown, from memory if you face the water wheel head on she'll be on an island to your left.

Just checked the wiki and you might need your flame to be +10 to see her but I think there's a little egghead guy (he has a name but that's way more fitting) who'll upgrade it for you. If you remember where you rang the second bell, go down the staircase and start attacking the walls, there's a hidden passage somewhere down there. You need to be infected with the egg head parasite thing for him to help you but it's not permanent as long as you act relatively quickly.
http://darksouls.wikidot.com/egg-head-infection

Ah found her.

Got pyromancy up to +12 so that's nice, though it still isn't really that powerful, even my most powerful spell (of which I have only 4 uses) doing the same damage as a single swing of my Black knight Greatsword. One thing that did come out of Blighttown was the fact that you simply cannot stick to one set of armour, you've got to switch it up dependant on the enemies and environmental hazards nearby.

After much suffering, finally got through Sen's Fortress and am now trying to negotiate Anor Lando. Currently at level 50, but the feeling of being grossly overpowered is well and truly gone - enemies can once again kill me in two or three hits, whilst they're able to take three or four of my hardest shots. The sense of imminent death at all times is quite wearying.

Do yourself a favour and don't interact with the huge painting on one of the walls, it'll take you to an optional area that you can't get out of without killing the boss which is probably too difficult for you at the moment.

I went in there accidentally on my first character and was stuck for a couple of days, it was pretty annoying.

Yeah, so I... looked at the painting.

Keep getting hit with toxin and have no moss left to cure myself. I think I did a stupid.

Have fun with the wheel skeletons.

Bloody hell, this is ridiculous. The bird-people can one-shot me, the fire throwing spore-head enemies inflict instant toxin unless I use magic on them, there's a bunch of spear throwing tough muthas in a courtyard, and those bloody skeletons down the well.

What level range is this area made for? It's murdering me.

Areas aren't made for level ranges per se but most people are around 60 when they go there. 50 is pretty much the average for Anor Londo.

I'm an idiot. I've been using sword and board for so long, I've forgotten my other options, namely my pyromancy. A single Great Chaos Fireball took out four of the pinwheel skeletons in one hit. Take that, bitches!

Well, that wasn't actually too bad. I died a fair bit but that was more due to lack of preparation, and once I'd got the attack patterns down I waltzed through the level, both bosses included. Got a knife from the invisible boss though, and it looks weak as hell... until you look at the bleed stat. Ouch.

Just beaten Anor Lando as well, took someone in to the boss fight with me and it was a piece of cake. Now I can warp between bonfires rather than having to run across the level!

Been tying up some loose ends now that I can warp around at leisure, including an unsuccesful trip to face Knight Lautrec, he who murdered the firekeeper at the Firelink Shrine. He and his two phantoms made me look foolish, so I obviously either need to gain a few levels, or change my approach. I'm going to try the latter, ditching Havel's armour (immensely sturdy but oh-so-heavy) for some of the Knight's armour I found earlier in the game, which while only offering around 2/3rds of the defence allows much greater movement.

Need to keep an eye on my stamina too, two handing a greatsword means it hits like a truck but I can only manage three swings and I'm out of puff. It also has the side effect of meaning that I need to time my dodges correctly, otherwise I haven't got the stamina to launch a counter attack.

I find myself in need of some advice. Any advantage obtained by my earlier overlevelling gave me has now well and truly gone because the last couple of levels, Tomb of Giants and now Demon Ruins, have thrown regular enemies at me that are simply overpowering, even one on one. Gaining levels seems to offer little advantage unless you can add ten-fifteen at a time, so I suspect I need better equipment.

I'm still using the Black Knight Greatsword + 4, though I suspect I've likely missed a superior weapon - I find it hard to believe a weapon I acquired in the second part of the game can still be the best available? I'm also seeing that dodging attacks is better than tanking them - my stamina is depleted in a single heavy hit, so evasion may be the better option. What are the bestlight armour options?

Basically dodge, a lot and make sure your weight to total capacity is kept at a ratio you are used to, basically it will change your roll speed and will lead to you fucking up later if you aren't used to the speed of your dodge. I can't give much more advice then that as you played longer then me, but its what i had to do being a low level for most of the beginning.

The truth is there is no best weapon at any stage of the game, nor is there any specific armor set that is better than the rest. That's not to say that some things aren't going to be better than others for you, it's just not very clear cut. I'll post what I can anyway though, hopefully it can be of some use.

Firstly I'd advise you to not level beyond 60 unless you really need a couple of extra points in a stat to equip something. This isn't important if you intend to solo the entire game but summoning phantoms can be extremely helpful when you hit a tough spot and if you level up too much it's going to make it difficult for you to find other players who haven't progressed to NG+ yet. Your souls would be much better spent on item upgrades than levels at this point anyway.

For weapons it's as simple as picking a weapon you can equip without leveling up too much more that also has a moveset you like and upgrading it to something that will benefit you the most. If you post your current stats and preferred fighting style I might be able to suggest a weapon or two.

As for upgrades there are two options that will probably be the best for you. The first is Lightning, which removes stat scaling from weapons but adds a hefty damage bonus. This would be good for you because, aside from the fact that Lightning is usually better than scaling until you get to NG+ anyway, I doubt your stats are allocated in a way that would be optimal for a weapon that relies on scaling. You can upgrade a weapon to Lightning by going to the Giant Blacksmith in Anor Londo once you have a standard weapon (this means your BKGS is out) at +10.

The second option, and the one I suggest you use temporarily, is Divine. This will reduce your base damage by a bit as it makes the weapon scale off your Faith stat but it does bonus damage against skeletons (TotG) and prevents them from being resurrected by the necromancers in there. You can get Divine upgrades by giving the Divine Ember from Darkmoon Garden (just past where the butterfly was) to the blacksmith near the entrance to Sens Fortress and upgrading a standard weapon that's at +5. As I said before I suggest you do this, upgrade it to +5 divine or whatever you can afford, finish TotG then revert it back to Normal and go for Lightning.

For armor just equip the best you can without weighing yourself down to the point where you 'fat roll'. The Elite Knight set from Darkmoon Garden is quite good. Also remember to use Havel's Ring if you need to. Most people end up choosing armor for aesthetic reasons, once you know how to kill something it's not actually important unless your build relies on poise.

Finally I suggest getting a good shield. If you're wielding your weapon with two hands the Grass Crest Shield, which you can find near a Black Knight on the way to where the Hydra was, is almost always the best choice as it increases the rate at which your stamina regenerates, even when it's on your back. If you're using your weapon one handed the Silver Knight Shield has nice stability (less stamina consumed on block) without being too heavy, it's a rare drop off the Silver Knights in Anor Londo, the bonfire just past where you had to run past the archers is a good spot to get one.

If none of that ends up helping there's not much else you can do aside from keep trying to learn the enemies you're fighting and figure out a way to beat them that you can comfortably pull off. Have you tried parrying? It works on a lot of attacks that it really shouldn't and ripostes are even more powerful than backstabs.

Weight to total capacity is 67/97 at the moment, though that is using Havel's ring to boost my total load. I'm aware of the change to the rolling (hence why I moved on from Havel's armour, which while having terrific defensive properties was half as heavy again as my next heaviest armour set) and have tried to keep myself relatively mobile, but for the most part my approach has been to tank and counter, which has worked well for 90% of the time. Now though, enemies are just too strong to make it viable, at least with my current equips.

Oh,a nd the Darkwood Grain Ring isn't helping any more, my load being over 50% essentially rendering it useless.

I'd get below 50% to use the Darkwood Grain Ring, the flip is awesome. If you don't want to do that you could go kill Lautrec and get his ring that increases your burden, max HP and stamina but can't ever be unequipped without destroying it OR fully commit to being a 'tank' (that term is relative in this game) and get the Wolf Ring from Darkroot Garden to boost your poise.

Current stats are approx;
Vit 25
Att 14
Str 25
Dex 20
Res 15
End 25
Int 15
Faith 8

Something like that anyway. I've got the Elite Knight set, though I put it in storage once I found the Black Iron set, which was only fractionally heavier for each piece, but offered significant protection gains, and the Grass Cress shield is my mainstay, it's my only equipment piece currently up to +10, even if it does only block 95% of physical damage. When I get my two handed swing on, the extra stamina recovery is invaluable, allowing me to make quick work of most of the bosses.

My faith stat makes me incapable of wielding divine weapons, and I fear I've grown so accustomed to the mechanics of the BKGS that any other weapon feels awkward and cumbersome. Appreciate the advice though, I'm determined to complete this first play through with out using a guide... even if it taking bloody ages!

EDIT: I tried fighting Lautrec in his realm, but couldn't successfully handle 3-on-1. Alos have the Wolf RIng, which proved very useful early doors but my poise is currently around 70-80 anyway, so not much stun-locks me anyway.

Try getting the Zweihander from the cemetery near Firelink and a Silver Knight shield.

The Zweihander has the same moveset as your BKGS with a much lower stat requirement, meaning you can 1hand it effectively, and the Silver Knight Shield at base level has the same stability as your upgraded Grass Crest Shield with 100% physical block which is EXTREMELY important if you intend to block things, I can't believe I forgot to mention it ages ago.

I'd still try making the Zwei Divine for TotG but Lightning will be better in the long run, as long as you kill the Necromancers you'll be fine.

I've actually beaten TotG, but it was a ball ache. The crouching skeletons (maybe giant dogs...?) were killing me in one flurry, though Nito himself was a bit of a doddle. Is the Zweihander any stronger than the BKGS? I can now comfortably meet the requirements for wielding that single-handledly, so unless the zweihander is able to utterly surpass the damage output of the BKGS it'd be a little pointless.

I've got several shields that offer 100% physical protection, so I do switch to them on occasions, but that stamina regen is just too good to pass up, especially when my fat arse is rolling around and trying to swing a greatsword in the same movement.

Wait, you must have the Black Knight Sword, not the Greatsword. The Greatsword requires 32 strength to use in one hand. The 'Sword' is considered a greatsword and the 'Greatsword' is an ultra greatsword according to the game, From Software's translations aren't the greatest.

Your current weapon only goes to +5 so you've almost completely upgraded it, as such the Zweihander wouldn't actually be an improvement damage wise until it was at Lightning +3, it's entirely up to you whether you want to change or not but don't stress too much about gear, it seems like you have decent stuff.

How weird. Yeah, the description lists the sword as a greatsword, but the title is just BK Sword. Apologies for the confusion. I'll check with the blacksmiths, see what my options are. Thanks again.

Must be near the end now, just took down Seath, the last of the big four needed for the Lordvessel to open the path to Gwyn. I'm trying to rustle up some enhancements for my weaponry, but a lot of the required items are in very short supply, and I still can't get any of the smiths to add lightning damage to my Zweihander, even though Anor Londo's smith will happily lightning-ify my shields.