GreedFall

This achievement is earned after you unlock all Technical skills and their respective upgrades. If you start the game as a Technical then Set Trap and Firearms will be unlocked automatically for you. This achievement should take a total of 25 skill points. Skill Altars will speed this up significantly. Remember that skills require at least 2 skill points to unlock, the ultimate skill will require 3 skill points to unlock so make sure to save some up. Upgrades for each skill only require a single point each. Here is everything you need to have unlocked to earn this achievement:

Firearms (Unlocked automatically when starting as a Technical)
-Precise Calibration (1 Skill Point)
-Destructive Shot (1 Skill Point)
-Impact Bullets (1 Skill Point)
-Rifle (1 Skill Point)

Anointed Weapons (2 Skill Points)
-Alchemical Dosage (1 Skill Point)
-Assassin's Touch (1 Skill Point)
-Focused Alchemical Fire (1 Skill Point)
-Alchemical Earthquake (1 Skill Point)

Set Trap (Unlocked automatically when starting as a Technical)
-Fast Traps (1 Skill Point)
-Destructive Elemental Preparations (1 Skill Point)
-Seismic Magic Preparations (1 Skill Point)
-Economical Alchemy (1 Skill Point)

Phial Throw (2 Skill Points)
-Light Grenades (1 Skill Point)
-Mephitic Discharge (1 Skill Point)
-Extended Stasis Alchemy (1 Skill Point)
-Devastating Grenades (1 Skill Point)

Bomb (3 Skill Points)
-Powerful Bomb (1 Skill Point)
-Toxic Bomb (1 Skill Point)

Once you've unlocked all Technical skills and pop your achievement, that means you have enough Skill Points to unlock all of the Warrior and Mage skills too. All you have to do is save your game, then use a Memory Crystal to reset your skill points. Make sure to select your starting class as Magic or Warrior to save some skill points by starting out with their respective skills unlocked. This will be the quickest way to easily obtain both: