The largest difference I have found with Art Licensing is that as an artist I have more in common with writers than I do editorial or advertising illustrators. When you make the transition to licensing you will find that you spend a LOT of time making art. Making and mocking up. Making and mocking up. And NOT getting paid for this time. This is a foreign concept to me. As a freelance illustrator all these years, I have gotten jobs, and created the work for the client. We go through sketch stage, revisions, final artwork, and voila, done. But with Art Licensing, get ready to work tirelessly, and then spend hours, days researching and sending your babies out into the world and hope one of them lands in the right hands, at the right time.
Do not get me wrong this isn't a bad thing, just different. I find that even as I migrate over to licensing, I am reorganizing the way I do art, and becoming more methodical in the art I make. I now spend time trend watching, identifying markets for my work, researching the visuals that I will put my spin onto, and then creating art. Once the art is created I have to put it on a product that I think the art is a good fit. I have spreadsheets of manufacturers, contact names, and I record what they make, and if I send anything I detail responses, what my follow-up is.
Now, my art is 'the product'. I manage the art similar to a small business person manages their creation. I have to find people to sell it to, just like any other manufacturer. So in many ways, my client and I share a lot in common. Art Licensing is very much so both 'business' and 'art'.