My two hobbies are weightlifting and quilting. I keep it to a minimum so I can focus my money, time and energy.
Weightlifting is great for my health, waistline, and happiness. I couldn't give that up.
Quilting is fun and I fit it in when I have time b/w work, husband, kids, and working out. I would hate to give it up...
As far as the doll clothes, I would look at what dolls are top sellers and the clothing for them. American Girl Dolls are popular and I think accessories are quite expensive. I am assuming there is a market, but I have 2 sons so I am not sure.