Dark Elf Fighter Skills (
http://www.lineage2.com/Knowledge/race_darkelf_skill.html)
Good place to start. Browse down the skills for each class and you get a good idea what each is 'specialized' in.
In general though:
[Palus Knight]: Self Buff, some defensive passives and a few attack spells/debuffs/skills including hate. Basically, you will open with a skill or attack, take aggro and then just beat the mob down. If you party, hate is good for taking aggro off someone else and putting it back on you.
[Assassin]: Strong attack skills with/and Bow and Dagger masteries. You won't have enough of either however to do much other than get an idea which you would prefer as your main weapon.
It's when you reach 2nd class change that things really start to pickup. Thus you will want to look at that class change before you make your first one!
Palus Knight -> Shillien Knight OR Bladedancer
Assassin -> Abyss Walker OR Phantom Ranger
[Shillien Knight] A Mage/Knight hybrid. Some very good summons/debuff/attack skills in addition to shield masteries and the Hate skills. Main weakness is the low HP/CON of the Dark Elf race, and the succeptability to stun. Actual attack power is greater than most other knights, (The human class knight, Dark Avenger comes closest.) although you won't reach the same hights as a DD class. (Assassin path)
[Bladedancer] You stop getting the hate/shield/armor skills, and start getting 'dances' (2 minute buffs) instead. You will still do good in damage output, but your defense stops improving. You work best in a party, where your dance effects are multiplied by the other party members.
[Phantom Ranger] A ranged class. You get a few ranged debuffs, and backup dagger skills, (Sting/freezing strike) but your bread and butter will just be shooting mobs with a bow and kiting the mobs as needed. You hit hard from a distance, but the debuffs require you to get closer as their range is less than your plain arrows. Not the fastest running archer, but a hard-hitting one.
[Abyss Walker] The dagger (DD) class for the Dark elves. Strong attack skills, a fair number of debuff type skills and the movement (Silent move/Veil) skills most daggers have in addition to some more pvp/situational skills. (sandbomb/trick) Daggers main forte' is the high critical rating of their weapon, but pdef/HP is low. Evasion is ok, but not spectacular.