Copy any of the little things you have seen so far and - above all - practice your PENCIL (or pen) CONTROL. Compare your last efforts with your first ones.
Steady improvement should be apparent no matter how self-critical you are. Remember no good artist is ever really satisfied with his work. If you are
dissatisfied it may be a good sign.
If you are practicing in a group, criticize each other. Try to make your criticism constructive. If you are practicing alone, hold your cartoons up to a mirror and see them backwards. This is a custom among many professionals - it helps them see their work with a "fresh eye."
Have you had fun so far? I hope so. Cartooning is a happy work. Sing and feel free as you draw. And when you're tired, stop. Remember, tomorrow's another day.