What do you really want to do? Am I lucky because I know exactly what business I want to pursue?
What you've done. I've already the experience, which is also the most comfortable transition to self-employment. Existing contacts, Potential Customers targeted, and I know the market and industry and maintain strong referral sources.
Your Hobbies and Interest. Why take something that's now a source of pleasure and potentially turn it into a source of stress?
Who do you know? Whoever it is, Be cautious, and make certain you like the kind of work your going into and whenever you inter into a relationship, put the details in writing.
What your good at. Why not use your skills? You may be the person your neighbors turn to for helping installing electronic equipment or decorating their homes. Perhaps there's a business opportunity there if many others in your community need the same type of assistance.
A Market Opportunity. Look around for what's missing in your community, industry, or profession that you may be able to provide Is it available locally? Do big company's neglect or leave this line of business that I can serve.
What you want to learn. One good way to learn something is to Start A Business Doing It, on the job.