How to study multiple difficult subjects?

Game developers should be able to write code, draw art and compose music. Is there a study plan or way to do all that without burning out?

Game developers should be able to write code, draw art and compose music.

Most of the time a single person doesn't do everything. So one way to not get burnt out is to find people to work with. Each discipline is hard to master so unless you've got a lot of time you'll not be good in everything, but having some knowledge in every domain (workflow, time management...) helps when working with other peoples.