Characters advance from experience. At lower levels, a character advances based on exposure, action, training etc. As the characters progress, the difficulty to learn increases because what they are trying to do becomes harder.

Advancing to Dots 1 - 2
After Intro scene.

Advancing to Dot 3
Requires using the 2 dot Attribute or Ability, in active play for a few weeks.

Advancing to Dot 4
Requires using the 3 dot Attribute or Ability, in active play for 2-3 months.

Advancing to Dot 5
This is the best you can ever be, almost unbeatable. Actively using the 4 dot Attribute or Ability minimum seven months.

Exceptions: Attribute Appearance cannot be changed after Character Creation.