Very simple achievement.
All you have to do is fully upgrade 3 skill tress
Here's how many points are needed for each skill tree:
Resilience - 14
Single - 13
Double Bladed - 12
Dual Wield - 14
Blaster - 12
Crossguard - 11
Jedi Concentration - 12
Telekinesis - 20
Confusion- 12
So Crossguard and two of the 12 point skill trees are the best for unlocking this quickly. You'll unlock skill points by naturally playing as well as finding skill point essenses.
Also worth noting you can reset your skills so then you can re-spend your skill points to fully upgrade other trees.