Host said: What are typical artist salaries? Do some companies pay a lot more for this position than others? What does a top earner make in this field?
What skills should you learn to increase your salary?
Huh??? "Companies" don't hire artists...at least not freelancing visual artists like painters, sculptors, printers, etc. (for the most part--there ARE companies that hire or contract these skilled people--such as Google--but it's rare). Since your question did not address a specific type of artist, ie. graphic designer, interior designer, mold maker, composite sketch artist, medical illustrator and so on, it is absolutely impossible to answer this question.
As far as the skills you need, that would be determined by the innate skills, talent, and interest of the individual. Real art is highly subjective and as varied as the mediums in which is can be presented. So is the "salary". =)
Some feel that you either GO to school or DON'T go to school. Learn to adapt your skill through educators or it's "built in" and there is no need for education. Going to school does give one some advantges like creating an instant peer group and support, mandatory gallery inclusion, and a culture in which to become socialized. Others just have a knack, a certain mix of intelligence and luck which can help them to find their way by street smarts, charisma, and self-taugh knowledge. Many from either camp just simply fail, are too insecure to pursue their dream, or lose interest and leave art behind to pursue others means in life. Can you see just how polar this field is?