There's have been some years since I don't play the game (started to bike instead of taking the metro) but I remember that the thing that switched from hundreds of games losing to winning one each 10 or so games was using all the available resources: potions, seeds, scrolls, throw weapons. Everything can give you a help little help, until you are strong enough. Also, saving the maps scrolls (each vendor have one)to skip past the last levels directly to the final boss was fundamental.
I’m a bit like OP and so far almost every potion and scroll is indecipherable, expect for the scroll of rage which feels pretty useless for a beginner.
For potion identification, if a floor have a "puzzle" room, there's a potion on the same floor to solve it. Like piranha room would have an invisibility potion, trap room a float potion and so on.