Even if you already know how to play the game, entering the Tutorial Dungeon
might be a good idea, as you'll get up to 15 free exp for disarming the traps in
there, while 10 xp is enough to level up.
Stick to lightsource items (Moonstone pendant, Dwarven mining helmet) on Ranger.
Even if they're a bit weaker in bonuses than their counterparts, additional range
will give you a lot more, as you can squeeze in a couple additional attacks before
the enemies get into melee.
When an enemy is one tile away from you, don't move in his direction but instead
pass one turn idly. Otherwise, after your move he'll be in range to hit you and
pretty much gets a free attack.
When fighting Orcs, make sure to stand on a tile that isn't already occupied by any
item! This way, even if you're "disarmed" (drop your weapon), you can just quickly
pick it up and reequip without the risk of having it drop on some neighbour tile.
(This is now redundant, as the weapon gets moved into inventory when dropped
while there's an item on the ground.)
If enemies are driving you insane with constant fleeing, consider using a poisoning
weapon (getting Venomblade asap helps) or zapping them with a wand of poison.
Poison is also a great tool if you're "almost" able to kill that troll. It will reduce his
Attack and Defence by 1 and add some damage over time, tipping the balance in
your favor.
Pesky trolls blocking your way can be easily removed by any form of teleport spell
by the way.
You can use weapons with knockback, Wands of Displacement and Cyclone spell to
push enemies into each other or into walls, and what's most interesting - also into
traps. Enemies which fall thru the trapdoor are instantly killed!
Save your Scrolls of Knowledge, Scrolls of Enchant and Bags of Monsters for later use.
- Scrolls of Knowledge are best used when about to confront the Goblin King. Make
sure to use them just after leveling up, not to waste any exp they might give.
- Scrolls of Enchant are best used once you are comfortable with your current items,
it would be a waste to enchant an ordinary dagger and then find and artifact one.
- Bags of Monsters generate charmed monsters which are based on the current depth.
Using them at the Halls of the Goblin King will most likely summon powerfull allies.