If you choose to plan ahead thats fine imo. I did it with Demon's Souls (somewhat) and Dark Souls. I watched all of ENB's videos before release.
Personally, I didn't think it took away from the experience, but it is something you really need to consider. They've given you good advice regarding that. Some people dont think about that.
1) 1st build almost = trash build...there's almost no way around it.
2) Upgrade you pyro 1st before anything.
3) No matter how you make your build, at some point, somewhere, you will be at a disadvantage. It is unavoidable.
4) Always summon Solaire...black crystal a phantom if you have to. If you do, make sure you leave them a present and apologize. You'll understand later.
5) Join the forest covenant when you can, you'll thank me later.
These are just a couple pieces of advice. I didn't want to give any spoilers, but you clearly asked for some advice.
As far as weapons and armor...
1) Dont stress about weapons or waste upgrades too soon. You'll find a weapon crutch in Sen's Fortress...if you can get there.
2) Get the Stone Armor from the Forest, or farm the Balder Knight armor in the Parish.
3) If you really like planning ahead, get the firekeepers souls early. There locations are here in the wiki.
4) Get the right of kindling as early as possible. There's an easy way to get it if you research.
I'm hesitant to say anything else. If you want elaboration, just ask.
Again, I'm trying not to reveal spoilers.
GOOD LUCK!
And welcome to the forums.