How can I stop working such long hours?
Firstly, you need to look at what you do and decide what tasks you can delegate. This will free up some of your time and will provide your staff with the opportunity to develop their skills. Even if they do it differently from you, don't interfere and let them get on with it.
Secondly, make sure you have good business systems and procedures and that they are understood and used by all members of your staff. If you have established what is the best way to do the various elements in all areas of your business, it will run more smoothly.
You won't then need to be around to make all the decisions.