How to raise GPA from 2.0 to 3.0?!?

Im just about to enter my Senior year in highschool, and i have been slacking off and playing around all throughout highschool... Now im realising that i need a good GPA to attend and take a Mech. Engineering class at ASU. My GPA is about 2.0... Id like to raise it to atleast a 3.0 by the end of my Senior year... Is it possible?!