I've just found a nice way to do advancement. I'll copy/paste it.
The standard Risus rules for character advancement will not be used. Instead, characters will be awarded a certain number of experience points per session. These experience points can be used to purchase any of the following character improvements:
Raising a Cliché: Provided the improvement is justified, the character may purchase the next level of one of their clichés. The cost in experience points is equal to the number of dice of the new level multiplied by 6. Thus, to raise a cliché from (3) to (4) would cost 24 points.
Gaining a New Cliché: If a character has developed in ways that are not reflected in their existing clichés then the first die of a new cliché may be purchased for six points.
It also had this neat section about sidekicks that I'm considering.
Hey son, wanna' learn how ta' make witch balls?