There are several rules of thumb to follow now that you've decided that you really want to pursue self employment. You'll want to do anything in your power to make sure you are in a good position to successfully transition from the working life to self employment nirvana.
As far as your new working environment is concerned, it is vitally important for your peace of mind that you somehow separate your working space from your living space. Unless you're able to make a space that you at least physically have to walk to, especially if it's in the same building you live in, the lack of at least a small amount of separation will cause you to feel as if you should be working at every waking moment just to keep up and your time becomes unstructured.
Self employment is very much about structuring your time in a responsible manner, so before you start, be sure you have a working space conducive to getting your work done, but don't go crazy spending money you don't have on an extravagant remodeling. Function is of primary concern here unless your business is in the arts, and even then, you should certainly keep functionality in mind. Put your mental energy into getting more business and perfecting your product or service.
You don't have to work all the time, though you certainly can expect rather long hours when you first start out. Not only are you establishing yourself, but you're evaluating whether or not the idea you had is a good one according to anyone else. It's reasonable to spend up to twelve hours per day in a new start-up venture. More than that and you are very much in danger of burning out.
Anything you can do to make these earlier days of self employment easier on yourself the better. You may want to accustom yourself to eating frozen or otherwise prepared food if you're used to doing all your own cooking, for instance. You won't have time for many of the hobbies you currently enjoy and will have to struggle to make time to keep up with even the basics.
Many people continue to work part time while they ease into self employment. This allows you to get a feel for if things are working out without betting the entire farm on the outcome. Sometimes, it's helpful to people just starting out with self employment, to have something else going on to give them some sort of schedule to work around.
The challenge of starting up in a self employment venture is great, but with some careful and meticulous planning, with figures, you can avoid some of the pitfalls that cause so many start up businesses to fail.