You could segment your market by different interest and hobbies people engage in.

These include:

• Hobbies - art, trains, computer games, gardening, crafts and so on
• Sports - fishing, golf, football and so on
• Health - conventional medicine, alternative medicine, diet, exercise, chemicals and so on
• Education - training programs, books, computers, videos ...
• Leisure Activities - hiking, theatre, reading, games, vacations and other activities
• Causes - environmental, social, political and so on

After you have segmented your market, the next question you need to answer is: what are you going to sell to them?