I'm a fairly experienced player; I have at least one win with every race, and also with every background available in 0.16. Here are the most important tips I've found for surviving with any character. My game noticeably improved after learning or figuring these things out. I'm not going to include everything you need to know to play. These are just the most important things that took me a while to learn.
- When you see an enemy, no matter how weak it is, you want to lure it back to a safe area to kill it. Always lure if you want to be safe. If an enemy shouts, other enemies will be attracted to the noise, so you should get out of there before they arrive; this is the purpose of luring. This is perhaps the number one skill for not dying.
- Always use blowguns. You can take out any pre-lair enemy that's not poison-resistant by shooting regular poison needles a bunch of times and walking away. Ogres and orc warriors are classic targets. It also works well on many dangerous uniques. With care, it's a fairly safe way to kill Gastronok or Nergalle, who are very dangerous to kill by other means. It's particularly good on Nergalle because the poison can kill her even if she casts Death's Door (once DD expires). You don't need to train any skills to use a blowgun effectively; throwing helps, but they work great at 0 throwing. Later on, blowguns are also effective on krakens and orb spiders, which again are otherwise hard to kill. Two successful hits with poisoned needles are sufficient to kill any orb spider. The game usually provides way more poison needles than you'll ever use, so don't be stingy with them.
- If you mostly kill things with a weapon, your weapon skill is the most important skill to train, but fighting is the second most important skill. It increases accuracy, damage, and your HP. Fighting is usually more important to train than dodging or armor, pre-lair. If you are a mage, it's most important to train magic, but fighting is your most important non-magic skill unless your aptitude is really awful. Not only does it grant more HP, but it lets a mage hit things with any weapon somewhat effectively, without having to train the weapon skill. I like to train fighting to about 10 before getting dodging/armor skill.
- Elaborating on that previous point, a human at XL 10 with 0 fighting skill has 63 HP. A human at XL 10 with 10 fighting skill has 85 HP - 35% more.
- Scrolls of teleportation are usually plentiful once you get beyond the first couple floors of the dungeon. Therefore, if you are in a situation that looks like it might turn dangerous, read a scroll of teleportation *before* the fight starts. If you wait until you're a few turns from death, you'll have to use more valuable consumables such as heal wounds, fear, or blink. Teleporting early is a very important skill if you want to live. Practice recognizing when a situation has the potential to turn bad. An ounce of prevention is worth a pound of cure.
- If you see dangerous things that you aren't sure you can fight or run from, skip the level. What qualifies as dangerous enough? Speed 10 melee attackers such as ogres, yaks, orc warriors, hill giants, hydras, or death yaks do not usually qualify. Even if you can't kill them, you can just walk away to the stairs and keep exploring the same level from a different stairs (assuming you're not naga or chei). Really dangerous enemies are fast, ranged, or both. Think grinder, Sigmund, Joseph, or early centaurs. Of course, it's safe as long as you don't wake them up. Beware if other enemies shout nearby a sleeping dangerous baddie.
- As you play, you'll learn which enemies are dangerous with different builds. But here are some general tips for the early game. Pre-lair, orc warriors, ogres, jellies, and ice beasts are the most common dangerous melee threats that you should not engage in melee unless you know you're strong enough. Always use care around orc wizards or priests. Centaurs are emergencies. In lair, the most common non-pack melee threats are black mambas, spiny frogs, and komodo dragons. Hydras are the supreme non-pack melee danger in lair; it's not advised to fight them in melee unless you're very strong. Handle blink frogs with ten foot pole, one or two at a time.