It's often good to revisit the basics.

This is ripped straight from The Rappelz Wiki, and it shows exactly what you receive per point of each individual basic stat (stones, buffs, etc):

 

As a Ranged attacker I gain 1.2 P.Atk per Agi point, which Melee and Mage attackers do not, though I get nothing but more carry weight from Strength.

It's a good idea to learn which stats benefit you most, and why. And whether you want to use basic stat stones or the stones that increase attributes directly (more advanced builds)