Its great to be able to draw mice. They make for excellent doodles, ornaments or cartoons on cards, and are fun to add to craft projects. Mice evoke a feeling of home, and, so long as you don't have a real mouse problem in your home, most people have fond feelings toward them. Though we make jokes about ladies screaming in fear at the sight of a mouse, we actually kind of like them (just so long as they live outside).
Mice can be drawn from the teardrop shapes shown below, but as you progress and practice you may adopt their basic shape to show their shoulders a bit more. Mouse tails are bald, too, and they have four toes on each foot. Their eyes are roughly the size of their nose. Adding a mouse to a drawing of the inside of the a room can add interest to your composition (especially if there's a cat watching), but it may turn off some people... the idea of living with mice is much more romantic than the reality.