I've found the best way to motivate myself is to give myself rewards. Doesn't always work though.
I need to buy a kitchen timer. I had one, but it is long gone. I like to set it when I'm taking a 'quick break'. 15 minutes turns into an hour very easily with me. The TV is also evil. I turn it on in the mornings to watch the news, but if I don't shut it off right away, I get sucked into whatever is on next. I've gotten good with shutting it off though.
The big issue for me is I always have good days and bad days. I'll go maybe a week straight being productive then it's like someone flipped a switch and I get nothing done. Writing wise. Other stuff I have to do, no matter what.
Food is a great motivator...except when it's junk food. I have to be careful with promising myself ice cream. Example: If I just finish that edit on chapter whatever, I can have a mug of ice cream. I'll end up get lots of chapters done, and eating lots of ice cream. Probably making myself sick in the process. (Can't have too much dairy.)
On a day to day basis how do you stay focused/motivated? Are you a daily writer? M-F? Or just whenever the inspiration strikes? I'm always curious about how other people do things. :D