If you have trouble getting things done, consider setting yourself a deadline to complete it. Done right, this can motivate and focus your mind on things that matters. When you have a deadline, it narrows your focus. You are now focused on getting that one thing done. It makes it easier to start and easier to achieve. Software companies like Atlassian organize 24-hour code fest (named Fedex day) to get new product ideas.
The time constraint you imposed on yourself can also help you keep things in check. Because there is limited time available, you are forced to do things that are really needed. 37signals used constraints to prevent their software from having too many unnecessary features.
The deadline itself should also be seen as a motivator. Sales and deals have a deadline for a reason. It gets people to act and over time, meeting deadlines itself can be a reward. But try avoid those deals if you can.
Obviously, none of this will work if you don't enforce the deadline. You could try set up some punishment for missing it or reward yourself for meeting it. Either way, tell yourself that you need to meet the deadline one way or another.
Start setting deadlines and maybe you can get more done.