I was thinking about making a walkthrough but I just made a video instead. I don't have a great computer so sorry for the quality.
This isn't a perfect run, I do make a few mistakes although all the strategies I use do work pretty consistently. I was on auto-pilot while recording this.
I take a Gnome Cleric/Thief through BG1 without using any equipment besides the starting quarterstaff and taking no reloads.
It might sound like a crazy concept but it is is really not that hard. It is just game knowledge, there are no difficult tricks. It just takes a lot of time to learn all the dangerous crap that can kill you. I forgot to add: the difficulty was Core Rules with Max HP.
I also wanted to take this opportunity to showcase the Cleric/Thief in general, which is a very underrated class and one of my favourites. If you are interested in a no reload poverty run, Cleric/Thief and Sorcerer are your two best bets if you are taking it through the whole trilogy.
If there is any interest I may make videos for other parts of the trilogy with the same type of run.