I think this is a fantastic idea

If you only draw and look at anime girls, getting into another anime-girl-centered hobby would probably be really good for you. Along with the other suggestions, I’d like to add coding to the list. It’s quite a difficult undertaking, but the possibilities are endless. You could combine your art with your coding skill and make a simple anime girl game. Nobody can tell you what you can and can’t do with the game. It would be yours. You could also post the game and find people who are interested in the same thing as you. There are plenty of people who share your specific interest, and you will probably meet some in real life. Comic-cons are your friend. — olly