If you're planning to reproduce your career sans corporate employer, you'll have to give us more information about what you already do. If you're looking into a different type of career altogether, read on.
I have my the transition myself (ex-engineer) and the greatest challenge has been setting the right level of expectations for my next job. How much I expected I should enjoy my next job swung from either too low (because by the time you quit I was burnt out and anything seemed better) or too high because of the type of effort needed to reach a point where you enjoy the work is completely different than the work output you're used to in the corporate world. That is on top of the typical challenges of finding a job that fits your skills, interests, etc.
It has been a long and rough process and even a couple years later I'm only now at the stage where I am getting the training for my next career actually started. If I were to do it all over again, I would have stayed at my corporate job longer, planned a structured attack of the problem in my free time, then quit as late as possible before starting my next job/training rather than quitting due to the uncertainty of how long it could take and the stress of continuing to work at the corporate job you don't enjoy.
My 'structured attack' would have included tech school "try it for 10 days to see if you want to do this as a career" type stuff (sometimes offered to high school students) or community college night classes in the same subject as whatever field of deeper interest I was considering (for instance, look at the BS/BA 4th year class requirements then take a lower level class of the same subject).
If you're open to hands-on careers and are stuck, consider tech school, possibly night classes, or even the military.