One of the most difficult things (for me) has been finding the appropriate balance (which changes depending on the context) between doing things myself, and delegating them to others.
What is the cost to you doing it? What is the cost of you delegating? What are the risks? What is the opportunity cost? (The opportunity cost is not your sleep, or your time away from your business. The opportunity cost is you having to delegate something else. The business will expand to the time you let it, anyway.)
As a boss, your goal is to become a multiplier. What can the team get done with your guidance as opposed to what it could get done alone, with you as a line worker?
But when all else fails, err on the side of delegation, because your first instinct will be to do it yourself. :)