Welcome to the DUC.
I'd think there is very little chance that people are throwing them selves over their keyboards to give you a free lesson in how to optimise your CPU usage. Especially without knowing anything about your setup, type of work/music, issues you're having etc. The topic is big, and an answer to your request would be very expansive.
So, if you're to get anywhere with this, I think it's best that you too make an effort, and explain your situation and issues in detail. Like; what does your typical session look like; plugins, VI's.
You should also give us an idea of where you are in the process of learning to use daws, and what music making experience in general, you might have.
Have a look here:
Help Us Help You
If you haven't already.