Most businesses start with an a-ha moment. You know the kind, it's the moment when something just fits together like a puzzle and all of the sudden it makes sense.
For me it was when I was laid off from my Finance job at which I had been telecommuting from home when my son was 18 months old and I realized I didn't want to start back with another company that would require me to travel or work extra-long hours. I liked seeing my son and I had to make my job fit that requirement.
I started freelancing by helping one of my old employers write a Finance manual and then a friend needed help writing a business plan and then another friend needed some training documents written and I was on my way.
Freelancing is wonderful. You don't get pulled into office politics. You can set your own rules. The downside is no benefits and an unpredictable work flow. Sometimes you are so flooded you can't see straight, other times you are nervous that you'll never work again. If you can make it through the first downtime, you'll survive as a freelancer.
For many of my clients, the a-ha moment comes at the end of busy project when they realize its not really the end but just the start of another cycle of running around crazy for someone else or when we go through life's transitions - job changes or family changes - and for others it is just time for a change. The key is often to find something that you actually enjoy doing and decide to do that for a living.
The first step to really starting your own business is deciding that you want to do something different. Once you decide you want a change, you'll be amazed at how fast the path for you will become clear.