You gather skills from where ever or whomever interest you in the moment.

Cunning Gambit

At level 3 you may perform one additional Bonus Action on your turn, which may only be used to perform one of your Cunning Actions from the Rogue class.  You may use this ability a number of times equal to your Proficiency Bonus, but only once per turn.  You recover all uses of this ability after a long or short rest.

Wiles

At level 3 you may choose a feat.

Knavish

At level 9 you can choose two more feats.

Skullduggery

At level 13 you gain any two feats of your choice, even if you have already taken them or you do not meet the prerequisites, such as species, class, or attributes.

Renaissance

At level 17 you gain the ability to give yourself advantage on checks against a chosen skill.  Each time you use this will grant you advantage for any one skill until your next short or long rest, even if you are not proficient in that skill.  You may activate one of these at any time and use the skill immediately with advantage, a number of times equal to your Intelligence modifier.