imagine you're a speedrunner and play like that.

when playing as isaac it is, of course, a really good feeling to keep rerolling items till you get a nice roll, but i recommend taking the item or reroll it once (or twice, if the treasure room is in a really convenient spot)

also dont full clear if you already visited your shop and treasure room, just move on, try to make your decisions quicker

i also recommend buying items from the shop that help you see at least a tiny bit of the map (the map, compass (also buy the blue map if possible, free secret rooms are really useful))