I would start with some voice lessons. Record yourself at intervals to see how you progress, it'll make you feel good! Pick up an instrument that might help, even if you don't use it for performing. Start networking and finding places to perform, even if not for money all the time. Stuff like that~
If anything, i would reccommend sending an inquiry to his business email (pewdiebusiness(at)gmail.com) if it's serious, he'll probably see it soon enough (it's also what he officially lists)