Best way to learn how to play using a controller?

Sooooooo. I got my Steam Machine the other day. And I'm old (think TAC-2 is my weapon of choice) and I can't get my head around how to train my brain to use the Steam Controller when playing action packed games. Games like SackBoy goes well, but aiming and shooting with the controller is down right impossible for me..

Any suggestions how to train my old brain for this, or should I just go and get myself wireless keyboard and mouse?