[petesalty]

Freelancing while trying to run a start up can be extremely tricky, I know, I've done it. I often found myself burnt out from client work (the work I didn't really want to do) which impacted the quality and quantity of the work that I did for the start-up (the work I did really want to do).

I'd say, if you must go down this route, really try to limit the work you do for others, take as little work as possible. Next, try and set times that you work on client projects, and times that you work on the start-up. Stick to the schedule you set up (put the start-up work in your most productive time slots). If you can't manage that, work like a demon on the client project exclusively, bang it out, then get back to the start-up asap.