Network, network, network and then network some more. Depending on what career path you want to take in art of course, if this is more of a commercial advertising thing it could be different. In the end, the more you get out there, promote your artwork, become friends with the right people, the more you'll see happening for your career. For art it can be a really slow process. There are tons of artists out there, its a big pool of talent with small spots on top if you know what I mean. But if you work hard and know how to make sacrifices, especially when it comes to time and money, it is always possible!
I work sales jobs, and have most of my life, and make what I want artwise.
Did a year on a commercial art degree, and as part of that interned at a place that made greeting cards, realized I did not want to be a professional artist, drawing what someone else told me to draw, how someone else told me to, and get it done by 5pm.
Art is a hobby, I sell some, I teach some, but I do not make near enough to even make much of a dent in the household budget.
That being said, SELLING your art is a completely different job than creating it. The few people I know making a living off of their craft are either specialized fields (stained glass) or diverse (paint's silk scarves, makes polymer clay minatures, does costuming for the local theatre) and both of the pepole I am refering to above occasionaly have to pick up a job during slow season to make ends meet.
People who create what they want, work another job and support their art that way.
People who work as artists, make what their employer tells them to make, and usually want to do something other than art while working.
Also, there are more artists out there, than there are job's for them, so job's for artists do not pay as well as other options, so it depends on what you are going for, and what ou want to do with your life.
Depends what you want to do first of all. How and what you may wound up doing is a whole other question.
The job requirements for a concept artist and a gallery artist isn't the same and it goes that way for every art job. Like, just because you can draw comics does not mean you can draw storyboards for movies and vice versa.
My day job is with a young software company where I draw concept art and other misc art stuff. I answered an add for a related job, gave an honest rate and it turned out they had a position opening if I was interested. I still do commissions and freelance besides that.
Your strongest pieces, keep it current and switch things out once in a while, take up jobs to build a resume, clients look for what they want to have done (this is why it can be a good idea to have different portfolios for different kinds of work). There are much better teachers than me who can help you in portfolio making. I'm also not too knowledgeable in the book illustration market and how to reach art directors.
how did you come about choosing art as your career? are there people who are pessimistic with your decision? what genre do you focus on? what are the most important things you must learn as an artist in terms of skill?
I chose art cause I love it simple as that, my parents and family and friends support my choice as Im trying to become an animator. The genre I focus on is anime as that inspires me the most. I most important thing to know as an artist is not to be a perfectionist and just learn things as they come.