The real trick to surviving the early game is to abuse the heck out of surprise attacks. Do not fight enemies in the open early on! Throw/zap stuff at them from a distance and then retreat behind a door. As soon as they step through the door, hit them! You should see a yellow ! indicating a surprise attack (guaranteed hit). Now retreat and do it again!
This trick works with anything that breaks line of sight. Doors and tall grass are my preferred options. It even works if you step through a door (closing it behind you) or around a patch of tall grass (to the opposite side of the grass from the enemy) and the enemy immediately opens the door or otherwise follows right behind you.
- Don’t leave a level without finding a ration
- Identify scrolls and potions as early as possible by using them in a safe context
- Use doorframes to fight one enemy at a time