Well, lomedehl, since you are still working on land shapes and general positions in a globe, the most I can suggest for now is to not worry at all about coloring/texturing as all that will depend on the biomes and such, which means, it depends heavily on where the continent is located, as well as how is it oriented (rotation wise) and where the other land masses are.

For now, the shapes aren't bad at all but, for realism, you can have the relative sizes vary more. I mean, compare North America and Australia, or Arabia and Africa...

Also (mind that this may turn a very "dark" path), if you want to go a little more scientifically plausible on this, you can think about tectonic plates. Have you read any of the active threads where people are doing this? This one, this one, this one or this one (and, possibly, many others, no longer active, down the archive)...