I work from home, so on break i walk to the fridge, open the door, look and then go back to my desk, and then repeat the same thing every 30 minutes
read online materials... I much as possible something worth the time. 3 mins facebooks is enough for me.
I don't give myself breaks, I just get up and make a coffee whenever I feel like it and bring it back I guess that's my break.
I find that time goes by a lot quicker when you're actually doing something constructive at work, I don't mind being busty at work at all.