In regards to my process, my ideas generate rather randomly. Sometimes I'll be working on one project when an idea will come to me for a different one. Other times I could be driving or watching something on TV or honestly, in the middle of a meeting and an idea will pop into my head. Sometimes I'm lucky enough to have something in hand that I can jot the idea down or even scribble it out, other times when I don't I'll have to try to remember it, or the idea will continue to grow and evolve into something else. It may not be a completely new idea, but just moving existing text around, or swapping out an image. Other times it could be a completely different idea.
In trying to be creative 40+ hours a week, sometimes my brain can drain so I've actually done little activities to help me break away and get the creativity flowing again. I've done the "30 Day Drawing Challenge" to help take me back to my "drawing roots".
There are shorter ones (5 days, 21 days) etc. and they all vary in tasks. There is one on Lynda.com for a 5-day drawing challenge that I've had in my playlist that I'd still like to try, and will maybe start this week. This one emphasizes different ways to draw (if you have a Lynda.com subscription you can view the video here).
Going "back to the drawing board" helps me see past the monitor and I think opens up more ideas for designs, so I try to involve sketching in my design process as much as I can.