After reading couple of work-life & time management questions, I'd like to ask, how much did you work, especially in the beginning (hours per week).
I've been making preparations in the evenings/nights for longer time beside my day-work, so working a lot will do. However, it is very difficult to believe that every startup requires very long hours continually because of different business models and requirements. (E.g. some may have possibility to delegate. Or it may be the case that business model is clear and ambition is moderate.)
Did you decide beforehand, how many hours is enough?
If you are the owner of the business then the buck stops with you. So, whatever happens, whatever short falls you have in terms of resources it will always come down to you to plug the holes which is why Jason commented as he did.
The amount of start-up capital you have also plays a huge role here. The more you have the more you can delegate/out source because you can afford to.
Without capital you only have two other options in the equation:
From the sounds of it you might be considering starting a business where some kind of service is what you'll offer. ? If that's the case, one point that Gerber (E-Myth) makes is that of discerning between being the business owner and being the one who does the work. These models where you basically offer your hours as a service very often end up taking up large chunks of your personal life!
I think it helps to think about what work you'll do yourself and what work you'll consider sourcing through other people. At least if you're working a day job, you should have some money coming in to pay other people to do some work.
It's hard doing too much in the evenings after a full-time day job.