What sort of mistake are happening in the company you work for at the moment?
-most small businesses run reactively always doing what is most urgent not what is most important.
Unless you are in the driving seat you wont be able to appreciate the difficulty of standing back from the the day to day running and making long term plans.
If you have a flexible boss, maybe he would let you do some private work? -you will then start to understand dealing with customers and getting paid.
These days the issue of personal liability is not straight forward. The standard advise is to become a limited company. In theory, wise, but in practice banks and landlords will nearly always require personal guarantees. Identify your personal liability is likely to be and assess whether you are still happy with the risk.
Running a business is not for everybody, if you can handle the stress it can be hugely rewarding. You will never watch the clock again.....only to worry there isnt enough time left in the day!