That answer is literally anything. Assuming you are not yet Picasso, check out your market and what is selling. Visit some local galleries and talk to the owners. Or walk through an art fair which are popular in the summer to see what people are doing and what they are selling things for. Also, I have purchased a great deal of art off EBAY from artists starting out who are fantastic but they just dont have a gallery or name yet so their stuff is affordable but likely still profitable for their means. For example, I recently purchased an abstract city skyline 24x36 original painting for $350 from more of an unknown artist but then I purchased a much smaller watercolor city scene from a gallery artist for $1100. The cheaper one quite honestly was better. If you have the ability to do commission work (aka someone tells you what they want and then you do that specific ask) and you have neighborhood blogs, you could put a message out that you are an artist for hire and see if you can generate some interest that way. Post a couple samples of your work so they understand your style. Art is so subjective and there is room for everyone. Gotta do your leg work and see if it is worth it for you and if you have the right talent to please your market.