1. their actions any more. I can remember all the fights I had until we started to use miniatures...cause they all had some special kind of action you imagined in your mind...I remember even our first session, just because I can remember the fun we had imagining a giant elk jumping out of the bushes, everyone dodging, and our brave dwarf saying: I´ll block his path... He went flying hahaha, he was not injured a lot, but his pride was so down, he hated all elks ever since >:-)
2. Do NOT give players powerful magic weapons...if you let them know they are soo powerful they won't bother talking, they just do not need it. We have been playing for 3 years in the world of DSA (the BEST german system, and the system with the most consistent world worldwide...) There ARE almost no magic artifacts in DSA, only the most powerful NPCs may have a wimpy "sword +1" or such... Also, there are no permanent magic items, they all have only some 1 to 10 charges, then they are gone...to slay a big dragon in that world, you would need an army, so there IS simply no way other than talking. Just make the players clear that they will die trying to fight this fight.

The better you describe your actions, the easier they will become, so roleplay is greatly encouraged. EVEN in combat. Try it that way: if a player describes beautifully how he TRIES to attack, give him a bonus on the hit dice or on the damage, or make the enemies' block more difficult.
3. Do NOT always stick to the rules, the people who make the rules are no superhumans, they are no demigods who exactly can tell you what would be wrong or right. Adapt the rules to your style, not your style to the rules. As long as a rule is the same for all (PCs and NPCs), it is fair. And even if NOT, it is your right as GM to tweak the game so everyone has max fun...so do it (you do not need to tell the players if they do not like such things). Like this you can discourage players who always seem to know the monsters Attacks, Blocks, Hitpoints....better than you do. Be chaotic, but be fair. If your player has a character he really cares for, a character with history, friends, family, tweaks, fears, hopes, dreams...do NOT let him die.

BUT if a character always goes out of his role, like a paladin always killing the enemies the most cruel way possibly, talk to the player...ask him about the char, ask him to write a story, to make a kind of blueprint of his chars personality. If he is not able to do it, if he regards his character only as a bunch of optimized numbers on a piece of paper...KILL HIM. It is cruel, but it is the only way to stop combat-addicted groups. Let them be killed or be heavily injured in combat. Let them have a trauma, a shock. Force them to develop fear of dying. No sane hero would fight till he dies (except the nice guys in AD&D with St 18/99 and Wis 6 Int 5 hahaha)
4. To make them fear death (combat with only dice rolling) make it worth living (roleplay). Let them fall in love, or get a province they have to care for, let them have pets like small dogs (pets who cannot FIGHT, so Basilisks or Dragons don't count ;-) ) When I played a Mage he always had a small monkey with him, who did tricks for children and the guys in Bars. He had found him in the jungle, with his mother dead, so he started to care for her like a mother. Imagine a powerful mage with a small monkey always asking for milk in medieval bars hahaha :-) If the mage would die, who would be left to care for the poor monkey?!

Let the players spend hours on thinking how their character is going to go on living...make plans, give opportunities. It's all called incentives...incentives to go on living. We were playing DSA for 3 years and no one ever died, cause it just would have been a tragedy. We were spending hours, days and weeks thinking about what our char was going to do next. I even knew how many buttons my coat had :-) When combat got hot it was not unusual for us to run away for a while to regroup/to rethink the action. We were REALLY afraid for our chars, cause they consisted of much much more than some simple numbers on a piece of paper.
5. Get a good system...YES, you have heard right :-) In my opinion it is very difficult, especially for beginners to do good roleplaying in AD&D, cause it encourages fighting. Get something like Vampires, and let the atmosphere thrill you.