speciesxxx, you should post one of your morgue files. That would help us see how you are allocating your spells and skills.
I suggest you play a High Elf Wizard. When you start, before you take a step anywhere, turn off all your skills except Conj. Then fire a bunch of Darts into the air (using the Z command). That should get your conj to 2. Now you can kill things much more reliably. Turn on your skills and start exploring.
Learn all of the spells in the starting book except for Slow. Watch your skill progression. You want Spellcasting going up faster than the other skills since it gives you more slots and reduces hunger.
Also, as soon as you find a sword, start killing easy monsters with the sword instead of your spells. Turn off the sword skill when it shows up. The goal is to pump Fighting to get your hp up.
If you are dying at ~10, in early Lair or Orc, that is probably because you have not found a medium attack spell. Throw Frost/Flame is pretty good. You can get those relatively easily if you worship Vehmut (assuming, of course, that the RNGs give you that choice...).
If you can't get the 2nd level frost/flame spell, then you can try casting conj flame as enemies approach you. Some will walk right into the flames (i.e., undeads). Stand next to the flames and melee the enemy while they burn. That will help vs some enemies.
As for the Imp suggestion, that works if you can find a nice biggish room. Summon like 3-4 imps, lure the enemy into the room, and use t a to have the Imps attack. Then you keep summoning more Imps to send into the fray as need be.
Also, don't be shy about using the Wands. The RNGs are usually very generous on the blaster wands. If a Spiny Toad is giving you a hard time, nuke away with the biggest gun you have.
Good luck man. Glad to see you are staying with it!
(Btw, do you play on WebTiles? If not, you should try it. If so, ping me if you see me (handle rootoo over there) -- be happy to watch one of your games.)