The fact that you are asking means you likely already have your values worked out.
Some tips (and BTW - I have 2 kids currently 6 and 9 and I started several ventures between 2005 and today):
1. Create Boundaries
Block off time for business related activities versus family time. And adhere to them.
2. Be Efficient
Eliminate time wasters and focus on your most important activities only. Delegate the rest (assuming you have someone to delegate to - if you don't then hire a part time assistant... money very well spent!)
3. Exercise and eat healthy foods
With the very likely sleep deprivation you're about to experience you'll need every advantage you can get to stay sharp. Poor fitness levels and a crappy diet will kill you! Short (20 minute) high intensity workouts and simple clean eating are the way to go.

A great resource for time management is Dan Sullivan's "The Time Breakthrough" http://private.strategiccoach.com/store/products/16

Congratulations and best of luck to you!