Learn to paint.
They are less "cartoony" (solid colors and black outlines
) and more impressionistic
. I honestly think they are some of the hardest things to create in the industry if you don't have a traditional background. You really gotta be careful when you throw around the cartoon label, people tend to think "oh its childish and there for simple and easy to do" and then they quickly find out its pretty hard.
There is a reason cartoons use solid colors and are overly simplified, that's because there are 24 drawings that need to be colored per second of animation, getting any kind of shading to flow without dancing and shifting requires some pretty advanced techniques and more often than not, some powerful tech.
That level of simplicity isn't needed in games like WoW, so drawing the paralell is a bit of a slap in the face to the artists that work hard to hand paint those textures. Mind you there are some awful textures in wow too... but its an old ass game and it's an MMO, so much crap to make...