I'm with patrickmclaren on "work out more," which will help you have better focus and energy. But besides that, figure out what works for you. Some people need deadlines or serious challenge and obsession (cough, cough, me) to work effectively.

So, maybe the deadlines? Start with the goal: Are you talking about building a company/launching a product? Pick a date, set it on some calendar that you look at all the time, and then set objectives/milemarkers that'll help you get there. Calendar those, and reminders. Set even smaller pieces into your calendar.

You can also get a buddy to check in with you/pester you, though that doesn't work for everyone. Or publicly blog about the deadline and your progress.