The best cartooning advice is basically to "keep it simple." If you want to create a character that is fast to work with, as in short comic strips, you need to consider a few things. The more details you create in your character, the harder it will be to get them right every time and it will take a lot of time each time you draw a new one--even if you know how to duplicate layers. There is a reason why many famous cartoon characters consist of few lines and not so many details. Look at Bart Simpson, Mickey Mouse, Dilbert, or other famous characters and try to imagine what it would be like to draw them repeatedly if they had big, curly hair with lots of details, a jacket with fringe, glasses, and beards. Unless you have unlimited time and/or want to create artwork such as that seen in the Sandman comic books, keep your character simple. The fewer lines the better. Moreover, that is where the challenge lies--to create a distinctive character with just a few lines drawn on your tablet. Pay extra attention to details as well, if you use them: Three strands of hair are not the same as two or four, and five fingers are not the same as four. The number of holes in the lacing of a shoe and so on are also important.