I made a poll/topic about this a little while ago, if you want to see the results and posts and stuff it's right -here-
Well, during weekdays I usually get it from candy, soda once in awhile, and sometimes tea in the early morning. To wake myself up sometimes I walk my dog Sharie and get a shower right when I wake up. On the weekends though it comes from 8-9 hours of very treasured rest!!
I think different things work for different people. But I'd say if you can, try taking a small brisk walk now and then and make sure you get enough sugar in your diet. Healthy sugar at least. Y'know like from fruit and stuff. I know you work out too, but I think that tends to wear one out. Getting a good dose of fresh air and sunshine always helps me. I don't recommend having candy and soda a lot even though I do sometimes heh what a bad example. I have cut down on the candy considerably though, I don't have it every day. I think you're off to a good start with eating fairly healthy and everything.
If you haven't got the time though, maybe energy drinks sometimes would be the way to go, like they said.