Biggest enner tip:
Use scroll of detect material to detect "enner beast flesh", teleport near him (not right next to him) and use FIREBALLS not striking. Striking does no good against him, fireballs usually takes 2, at most 3 shots.
Use any armor you can find, no matter how crappy it is. You'll replace it as you advance. Even soft shoes work wonders when it comes to blocking weak enemies. Decide on one weapon type and stick to it, don't use swords at one point and then switch to spears. If possible, don't rest to heal, just walk around. That way your endurance won't go up too quickly and the enemies will remain easy. If your health is really bad, drink healing potions instead of healing. This will also keep your endurance low, and don't worry, you will always have plenty of potions.
I think a lot of people don't make it through UT most of the time, I certainly didn't. You'll get better with time and through browsing the forum. How do you usually die? If you tell us that we can give more specific advice.
Oh, and welcome. I'm the admin but I don't do much administrating