When you are self employeed, you alone motivate yourself. There is nothing stopping me from getting out of my chair and doing any damn thing I please. I could watch a movie, go to a party, or hop on a plane to Miami. Whats going to keep you working when other people are practically dragging you away to do these things?
First, ask yourself — what part of the business frustrates me the most? Frustration is the fast track to burn out. You need to isolate specific tasks that make you irritated, angry, or unhappy. Is it creating CSS designs? Programming Java? Updating your software? Writing?
If eveything about the business frustrates you, stop. You are in the wrong field, you need to find something else to do.
Your best solution for combating frustration is delegating the task. Hire an employee. If you can’t hire an employee, bring on a business partner that loves doing the part you hate.
Repeated Failure to produce measurable results is the next cause of burnout. Two years ago I worked on a site for a full month. I researched, I wrote, I tried building links. Ultimately, the site ended up making a couple of dollars a day.
Had I repeated that process again 12 times that year, I would likely not be in this business today. Instead, I learned from my mistakes, cut down my site development time to a week, and made sites that did not have the stopping points of the first project. Instead of chasing the high cost-per-click words, I built sites for niches with minimal keyphrase competition that I knew I could get backlinks to.
As a self-employed business owner you control your direction. Employee burn out is different. As a subordinate you have to figure out how to cope with a confined set of circumstances or quit. If your or an employee or student I can not help you, but you might want to check out this list.
In order to flourish, you need to create an enabling environment around you. This is just as important as evolving around factors which you can not control.
Perhaps this is anecdotal, but the most successful people find work to be an object of desire rather than a means of survival. It attracts them because they do the things they specifically enjoy, and let others handle the rest.
Do not let burn out kill your dreams. Fight it, just as you would any other obstacle.