Learn to realize when getting on the internet is an impulsive need. Manage your time to include more activities in a day and less time spent doing each (like the internet). Live your life with purpose, when you get on the internet keep in mind what you need to do on there and get off when you are done. When you wake up make a SMALL list of things you want to do that day, and think about the next day too. Keep it small. Get yourself out of the habit of internet.
If you really have problems controlling yourself you could use a number of parental control programs and have a friend set the password over the internet using logmein. Some routers will also offer parental filtering.