Most important thing for any entrepreneur is to keep his or her sanity because it's a thankless job or as someone says it's a very lonely job.
I tell a lot of people that when you set your milestones keep them bite-sized small. Milestones that you can keep measuring, that you can keep recording and that you can keep holding people accountable to.
The human mind has been conditioned to solving all the problems on its own because if you reach out to someone for help it is seen as a sign of weakness. Nothing could be further away from the truth than that.
I always tell people seek knowledgeable mentors, look for good advice and more often than not you will have someone who will put their hand up and volunteer to help.
When you start getting into a much larger scale it is the systems and processes that drive the organisation. Therefore, at each stage you need different skill sets to be able to manage it
Keep your head down, keep working, don't let problems hassle you, keep delivering, keep communicating with the people, and most importantly keep yourself fit enough to be able to work that 18-20 hours a day.
There is not a single day when you can say that I'm going to ease off. Even on vacations the phone was always on, email was always on, but it was fun!