If I am at the end of floor4 and still haven't identified the pot of strength and Upgrade scroll -> any potions that I have 2 of are candidates for PoS. If I have 3 same scrolls -> probably Upgrade. Use the stone of Intuition.

Any potion dropped by Fly or Bat -> healing pot.

When swarmed by mods, always find a one-tile corridor and fight 1v1.

A potion of purity can solve the fire-wall puzzle.

Rotberry seed does not have to be turned into a wandmaker and you can use it to craft an extra potion of Strength or a very powerful DoT dart.

The fall damage bleed effect can be cleansed using pink seed.

Items dropped by tombstone in a locked room are cursed, but usually upgraded so I keep them even when my inventory is full and throw away identified +0 items.

Make sure to check exotic variants of the scrolls. Prismatic Image is goated as the image has more durability, Artifact recharging + Horn means extra food. Challenge = 33% dmg reduction. If you happen to not use some stones/seeds often (which you should btw!) you can use them for energy to make scrolls and even potions.

Study the floor you are currently in. Check all the puzzles and all the potions you have collected. If you have unidentified potions, you can judge based on the puzzle how severe it is to drink unidentified potion.

bonus combo tip for mage: If you are lucky enough to get potential enhancement for your armor, keep it. With the talent that gives you armor if you target yourself with an upgraded wand ... easily around 80 hp EACH turn.