. +DEX : increased fire rate for cubics.

. +WIT : faster heals.

. +MEN : more MP.

ShilienElder
Note that you cannot change your INT stat. you may want to try to get an avadon robe set to +6. any weapon with acumen will do.

. +CON : increased survivability in PvE.

. +MEN : this is essential as you will run out of mp otherwise.

. +WIT : this is also essential, to increase % restored with "resurrection" and fast heals.

SwordSinger
If you go +DEX goes all the way with +5, same with STR if you go that way. you have a wide  Lineage 2 Adena variety of weapons to choose from, because unlike the blade dancer you can sing with any weapon.
Every SwS should have a bow, but there are two basic melee setups, sword and shield or a two-handed sword. tallum heavy and a dark legions edge with critical damage SA or blue wolf and Damascus with focus or crit damage SA (go with crit damage if you frequently run around with full buffs) with a shield, or greatsword with focus or critical damage SA and majestic or heavy.

Nightmare light with a dragonslayer with critical drain might work well for a solo setup.

. +DEX : increase in crit rate for more damage.

. +STR : increases damage, never a bad thing.

. +CON : higher survivability, but will not make you a solid tank  Lineage 2 Adena in PvE.

TempleKnight
By increasing your attack speed, you increase your cubic fire rate. tallum heavy and a tallum blade with the haste SA is one way to do this. though a dark crystal shield will look better, a nightmare shield will work better.

. +DEX : allows you to run off the raid boss when things go bad, get trains for AOE, and increased fire rate for cubics.

PlainsWalker
You are the fastest dagger, with the highest crit rate. dark crystal light looks like it would be a good armor set, or nightmare light if going against magic wielding  Lineage 2 Adena mobs/players. you may want to try to get a doom light set to +6. get a dagger with focus or critical damage.

. +DEX : increase in crit rate for more damage.

. +STR : more damage.

SilverRanger
You are the fastest archer, with the highest crit rate. +STR really isn't your cup of tea, but it doesn't hurt. you may want to try to get a doom light set to +6.