I have Found this Guide to be helpful and very informative. i like how the skills, and stats and combat system are broken down. i like how the combat system makes the player have to learn how to play their character, instead of just standing in one place button smashing. you have to learn to find the balance between Damage/Control/Support.
This guide is by the best i have found and the most detailed everyone should read this guide if you want to be the best at your class.