Class guide - You know it's always changing, but here are some basics
Let me get this out here first, the classes are pretty balanced in after level 70-75. This means you don't have to roll a certain class in order to be competative. Enough said, let's see what I can clear up for you
Warriors
Alright you have two choices basically dps or tank.
Stat priority (Applys to gemming, DS, enchant order, etc.)
If you choose dps: HP, Patk, Dodge, and then round out the rest with defense and a little crit.
Party formation: You'll be in the back center row behind a tank hero (rose knight/shadow wraith etc). Use the angel halo, if you have a mage/healer she'll want agility or Matck bonuses, usually in the back corners.
If you choose tank: HP, Dodge, End, Patk, then def and block (if you find your dodge is high enough, replace block)
Party formation: Well you are the tank. So front and center baby, be a good meat shield for the rest of your party. Typically the healer (because she's the most squishy) or your best dps will be behind you in the center. This gives them the best chance of survival.
You should not need hit at all, you have passive abilities to increase your hit. If you are finding yourself missing often, -one- hit gem is ok, more then one and you're doing something wrong.
Dragon souls should follow the same pattern. Because the player DS abilities are so crappy, you have the option of forgetting the 80/80 thing and instead stacking up on HP/Dodge/Patck. Especially once you're using topaz and ruby souls, it starts being worth it.
Mages
Here you have two options, what we like to refer to as a balanced build or as a dps glass canon. Balanced gives you a bit more surviability. The other is pure massive dps, but if they hit you, squished mage.
If you choose balanced: HP, Matk, Agility, dodge, mdef/pdef, crit
Party Formation: Based on angel Halo, definately back row to start look for either Matk, HP or Agility. Tank should be in front of you unless you have a damn good reason otherwise (like keeping the healer alive, but only if your dodge/def is high enough to live on your own).
If you choose pure dps: HP, Matk, Agility, Crit, Hit (if needed, in this build even missing 10% of the time is too much. if not needed then the defenses), dodge
Party formation: Back row, corner with a tank in front of you. And it needs to be a damn good tank, preferably with a taunt later in the game. Once you can open up all six gem slots, you'll be a little safer since you can get your dodge up.
DS - get the mage rez ability. Here's also the point where you can add hit or defense as needed
Hunters
Really hunters have two classes, both dps, one just has more buffs and a little less straight dps.
If you choose pure dps: HP, Patck, Crit, Agility, Dodge, p/mdef
Party formation: You should be good in any HP, crit, patk, or crit slot. If your def/dodge is high enough you can be in the front row, otherwise use a tank in front of you.
If you choose support dps: HP, Patk, Dodge and the rest are going to change as you unlock your passive skills and abilities
Party formation: Back row HP, Patk, or Crit
DS - Just get the damn shield from radical. If you come up against a pvp situation where the angel is crushing you, try the other one, but the shield is better most of the time.