This is a no-brainer. Good art can make a good game into a great one, while mediocre (or god forbid, bad) art can kill a game before anyone looks between the book's pages.
Example timeThis is the cover of my Remnants game:
If you look inside, you will find more mechs drawn by the same artist. Some of the work was licensed, and some was original, but it all worked pretty well. Above all, though, that cover knocked it out of the park.
Getting that cover was a lot of work. My artist lives and works in Germany, while I'm in Canada. This makes scheduling any kind of real-time communications tricky. There were a lot of early morning and late evening Facebook and Skype chats to get it all together. After scheduling comes concept designs, followed by draft after draft as we narrowed in on finished product. Even the font we chose, Criovision, was not approved for commercial use, and I had to contact the South American company that created it to get permission to put it in the book.
The WaitingThe fallout of all of this is that art takes a lot of time. From first email to finished cover took months. You also have to remember that most of the artists I work with do commission work on the side, and only work for me on evenings and weekends. All of this adds up to weeks and months of waiting for art. It can be frustrating, and it has held up several projects in the past, but when a new email comes arrives with new art attached, it's like getting a Christmas present.
My experience working with artists has taught me a few things:
1. Get the best artist you can afford, especially for the cover. A good cover will draw people in. A good game will get them playing.
2. Give your artist a long leash when it comes to image composition. While they need direction in terms of what to draw, let them surprise you with their interpretation of your ideas. My artists have always produced their best work when they were able to use their imaginations and go in directions that I never thought of.
3. Keep the business part of the deal simple, honest, and straightforward. Be sure to agree to a payment system that gives at least a partial advance upfront, and then more upon the completion of the work. If you ask for lots of changes, you should expect to pay more.
When it all comes together you get great art and a beautiful book. For example, I got some art for that other game. Here's a sneak peek: