Class Basics

Part 1: Skills

Put Bonus Points into Skill Proficiency first.
You will start out with +12 tier 1 armor so you will not have to worry about getting armor till past level 50
Don't invest in Stats early in order to use higher tier weapons or armor.

You can reset your skills 5 times before level 40.

Some skills are more useful than others and some skills are useless or made obsolete by later skills.

Part Two: Stats

After deciding on a build (Pure or Hybrid) it is time to invest in Stats.
The goal here is to get the Stats to use Endgame gear

From the ijji forums (compiled by Vivislash):
STR: Physical Attack Power
AGI:Adds Dodge
(think it helps with crit in this game but I don't remember)
VIT: Adds Def and HP
SPI: Adds mana or sp. The more you have(spi), the faster it recovers
(Idk if this has been tested, but it's rumored to help Ele with their Crit as well)
INT: Increases magical attack

Depending on the class I believe the affect can differ slightly or even be more potent.

Edit: Skill Proficiency also adds damage.
Edit: SPI, I meant the more SPI you have the faster the mana recovery.

Edit: AGI(Winter+Onrop)AGI: Dodge, Critical Chance, Physical Attack Power, Hit-Rating, Movement Speed, and Attack Speed.

Part Three: Equipment

The last part of building up a character is farming high end encounters for equipment.