Best advice: Do something you love.
Otherwise, there's a bunch of strategies and practices out there. If you google for this stuff you'll find quite a lot and there are plenty of books too. I couldn't possibly cover this whole area fully but I can give an overview of some of the stuff I've encountered.
In The Now Habit, author Dr. Neil Fiore talks about a positive attitude to work. Work can be enjoyable, and should be. Parents, teachers and bosses often use language that suggests that unless you really push yourself and are suffering, you aren't working properly. He suggests that you make time for guilt-free play and that you decide to do work, or not; don't talk to yourself in "I have to's" or "I should really's". This has had quite a positive effect on me. Of course he backs all this up with explanations of why we procrastinate, saying "we procrastinate because it makes sense", and how perfectionism and workaholism are closely related to procrastination.
David Allen, author of Getting Things Done (GTD), talks quite a bit about how maybe the reason you don't want to do something is because you haven't got enough definition/clarity over what it is that needs to be done, specifically you haven't defined the very next action step. He also suggests something that Timothy Ferris, in the Four-Hour Work Week, expands upon greatly: Maybe doing it isn't really that much of a good idea and you know it. I have a better understanding now, than I've ever had, over the different types of not doing are. There are at least four that I can think of right now:
- Genuinely unpleasant/overwhelming: Procrastination.
- Incubating indecision: Deferring a decision until a time when it can be made more easily, perhaps due to new information or another decision you can make that sets precedent for the one your indecisive about.
- Batching: Leaving something to accumulate so that you can do a whole load at once more efficiently.
- Waiting: For someone or something else.
Timothy Ferris talks a lot about not doing the things that you don't need to do. Shit, its amazing what you don't need to do, especially when it comes to other people bending your arm to do things for you. I'm only now just learning to say no to people and it's fantastic! I'm still trying to hone my skills so that I'm doing the important things as often as possible. Identifying what is important is hard.
Final note: This stuff is very individual. If you can, keep a procrastination log for a while (this is advice from The Now Habit): Whenever you procrastinate, detail, what you are supposed to be doing, how you feel, why you feel that way, then, what you ended up doing, and how you felt about that. This is very revealing of what's going wrong and the direction you might need to take to correct it.