It's tough to able to make it as full-time, professional illustrator. Most people have another job and do as much freelance work on the side as they can. There are a few who steadily increase their freelance work and eventually transition into full-time work, but that's rare.
Check out the Society of Illustrators, they have lots of competitions and publications every year and can be a good networking tool and resource as well.
I am wondering here why the end goal is to be an illustrator? It's not a particularly high paying career, and has a lot of competition for the available work.
However, the best way to start, is to do it. Take a can of soup, an oinion, a bottle of salad dressing and a cup, put them on the table and draw them. Then take some fabric, like a bedsheet, toss that over the stuff on the table, and draw the drapped fabric. Then place some items on top of the fabric, and draw another still life.
Still life's are great for building skills, they let you translate 3D onto a flat surface, and hold still, so you can compare your work to the original.
Draw everything, your shoes, the bedroom you sleep in, the building the bedroom is in, the cars on the street, trees flowers.
Then branch out into animals and people.
If your end goal is illutrator, you are going to need to be able to draw everything, might as well start now.
Aside from the loomis books Drawing from the right side of the brain, and anatomy for the artists are both good books.
well...the most important thing is practice. practice practice practice.
You should draw some things and look for helpful advice how to learn the things you want to draw. For myself I just startet with an artwork and then I couldnīt stop. And in the next years I found out about the ways I could learn.. Oh..I donīt know much about books never used them..I usually use references and practice on them. maybe you can visit an art class if you find one..Just matters if itīs a good way to leanr for you. And another thing...until you are good enough to be profeesional it will take a lot of years. Donīt forget that.