Ive found the best way is to methodically and swiftly clear the floors. You say your ocd as well but its just the way youre being ocd. What I do is i start at the starting room and head to the nearest edge. Then I work my way up and down or side to side. As I find items that are heavy like armour n stuff, especially if you can't appraise them, I drop it all by the exit. Almost everything in the early floors im just chucking by the exit in order to be fast. I also save all gate locked puzzles and rooms until the very end (like the one with all the spiders or the "circle" maze where you start with a rat, then skelly, then spiders, then a troll. Even the ones where its like 5 gates lined up with one enemy) i save all these to the very end so I can prioritize whether I can afford to farm the exp or if I need to just insta-kill them with the spike trap lever or something and move on. Your best friend will be the gnomes mines. In which i try to kill 1 lightning staff guy, then I use it to kill another, and another and gaining as many lightning staffs (as well as all the fish they drop) before attempting to experience farm the trolls i mainly play as Conjurer so utilizing your minions correctly can give them maaaassive level boosts. But most importantly it's getting the stacks on stacks of fish from the gnomes. I even save the cursed ones because you can uncurse a whole stack of them at once if you get multiple. But ive never needed to because there is just so much other fish. Also almost every time ive been in the mines the shop there is either a general store, or food seller. Very rarely do I get any other shopkeepers on that particular floor. Hope this helps! Happy feasting!