I'm not sure if this a work question or a life question. I'll take a stab at the work question.
Here are the prerequisites for my motivation-
1. No fear
2. Knowing that you are doing something worthwhile, exciting.
3. Confidence that you can accomplish the task to your desired outcome.
If I don't have these I procrastinate. But procrastination is a good thing sometimes - it makes you work more efficiently when you are under the gun. I am a professional at this but it has given me much grief lately and frankly the anxiety sucks.
If you just don't want to deal with the stress the trick is to fool yourself that what you need to do is really fun or interesting. This usually does not work for me so here are some other tips.
-I find once I start doing something it is not as bad as I thought it was going to be and usually just need that inital push to get the momemtum going to finish a project. Like organizing my desk or the project files or creating the outline or game plan.
-Start out small and just do the stuff that is either easy or fun to do - like organizing files for your project or finishing just that piece that is effortless, continue doing this until you get to the hard or most unappealing parts, by then you would have gained momemtum.
-One reason why I procrastinate sometimes is that the project seems so daunting and huge that I doubt that I can finish it in time at the level of quality I want so I just break up the tasks into a kind of checklist so there are a bunch of smaller tasks that are not as daunting which can usually be done in an hour or two each. Make a list and check these things off, make things more tangible, clear, and controllable.
-Dedicate maybe 10-20 minutes a day at the same time every day - say 8pm at night and just do your work. Just say I will endure this hell for 20 minutes. This works for me when doing taxes.
-Get it out of your head that what you do needs to be perfect the first time around. This is the big thorn for perfectionists like me prone to procrastination. It is always easier to work with something and change it than it is to work with nothing.
-Rewards after finishing something never work with me. My brain just can't be bullshitted so I won't mention it here. Never works. And projects are never 100% done they just are completed to the point where the time and effort you have allowed for it. They often come back like a rash.
In the end it is always easier to do nothing than do something and get off your butt and risk failure. But nothing ventured nothing gained.
Failure is never fun. Just realize that it is the best way to learn though. Everyone fails but it's the smart guys that learn and get better from it. Also this may sound cliche but don't be afraid of failing, don't tie a lot of your self worth into that. That emotional let down gets in the way of objectively getting the most benefit of learning from that experience.
If it is a life motivation procrastination thing - start exercising. Become more active. It will change your perspective on things, make you feel emotionally, and mentally healthier. You will feel better about yourself and that will spill over into your motivation in life and confidence to pursue what you really need to do. Just do it. Or get someone to make you do it. If you can't motivate yourself competition and words of encouragement and advice from friends can do wonders.
Best of luck to you.