take note of what sells, for lots of money

Well comics take a lot of time and effort but they are a popular product for such themes?

Have you tried macro?

Macro and muscle are pretty popular themes here. They can enhance sexual and erotic scenes pretty well.

Breast Expansion?

It's simple, really. Just keep on drawing.

More chubbies with huge breasts!

I don't know.0.o

Accept commissions from people, and draw more stuff you really enjoy yourself. Collect ideas from others! :3

Just keep doing what you are doing. ^^

You're already doing very well. You don't need to change much to get to the top.

It's like the others said.
Concentrate on your themes of art while still crafting out ideas as you continue to do art for yourself and your clients.
And Then expand even further with it by working on different stylings of art as you continue to develop your talents and crafts more.
You have the knowhow in doing Big Busty Women, the Size and the Postures of the various themes you have with your works. Just keep focus on the different stuff now and then and you'll do fine with Submissions and your own pieces of Grand Art. mono.
Thanks for posting, remember what we said well towards adapting your craft and stay burnin', Always.

Yeah, just enjoy yourself, and do what the commissioner asks for. if it's not too crazy I would say. Just keep up the good work. I can' wait till I can commission you myself.