ADOM has two kinds of fight: melee and ranged. If you want to stay alive long enough, you should train both types, and don't be afraid of it. For ranged attack it's best to have one of: speed, Archery (for the sake of Lightning Shot) or Concentration. Speed comes to: Archer, Barbarian, Beastfighter, Monk, Ranger. Archery: Archer, Assassin, Farmer, Fighter, Healer, Ranger (and Hurthling). And these classes should be chosen by weakling races, because later in game they will be able to avoid hand-to-hand combat with baddies, and earlier they need better toughness, training in melee, better gear and so on.
Concentration comes to: Archer, Druid, Elementalist, Mindcrafter, Healer, Monk, Necromancer, Priest, Weaponsmith, Wizard (and with a Charged talent Dark Elf can be considered a mana battery) and these are classes to be chosen by stronger races, because they need firepower for the later stage of the game and in the beginning their HP is high enough to not be killed by a door.
So what I'm trying to say is that I strongly discourage playing elven magicians or orcish fighters.