Nothing worth doing is easy. I can't give you a specific plan because each of you is in a different place in your life. I will be giving you some specific things you can do.
First remove the garbage in your head, we tell ourselves that we can't do things and that others have advantages. When you catch yourself doing it, stop. Everyone does it, winners just work harder at stopping it and direct their efforts to things that take them to the next step.
Start with commitments and reality. Write down the reality of your situation/commitments so you know the moment you can be free. For me it was my living conditions and family that I needed to contend with. I knew if I did not do art, I could not be happy. So I made up my mind to work on my art everyday. I found a way to show my works in galleries, festivals, local businesses etc. By working toward my goal, even just achieving part of it, I saved my sanity. Every year is an ongoing process for me, working toward new goals.
Lay out your needs and where you'd need to be to quit your job. Set a five-year goal to sell enough paintings monthly so you could quit your job. Set annual goals that grow each year, and worked all your spare time beyond family and job to hit those goals. On weekends visit galleries. At nights or any spare time, do your art. You will find that time if you stop watching tv, stop playing on the computer, sleep less, etc...You have to be driven and work doubly hard. You may have to work extra jobs for a year, or a few years, to save extra money. You may have to work late at night and on weekends.
I am obsessed with never allowing myself to miss my goals. I scold myself when I do, and I make a point of making it up in the next month on top of my new monthly goals. Refuse to give yourself excuses. Share your goals with your loved ones and ask then to help hold you to them.
You will have to work longer and harder than you did working for someone else, so be prepared. Taking a budgeting class would probably help if you need to to get finances under control.
Do your homework to find out about taxes, getting your DBA, copywriter, insurance, etc...
I hope you find this information helps you in your own career.