Mark Witton has some advice for you

Mark Witton in noting that no one (qualified) has ever put together a straight forward guide into launching them self as a palaeoartist, has gone and created one himself. I found it very useful and reassuring, speaking as someone on the cusp of breaking in into the "industry" (knock on wood), and so I heartily endorse you to check it out too. (It is also reassuring to see that the little advice I have tried to give in my own posts is nearly the same as Mr. Witton's... That'd have been embarrassing if it weren't ;P )