Here are a few ideas that will help you better manage your time:

1. I know of a lot of people that will sit in front of the computer for 10-15 hours at a time and not accomplish a thing. Try focusing for just 3 or 4 hours at a time and you will get a lot more accomplished.

2. Take a Break! Its important to walk away from the computer or your desk and let your mind relax for a few. Eat lunch, go for a run, or walk the dog. Anything to give your mind a break from work. You will have a more focused train of thought by doing this.