One way to get ideas for characters is drawing freehand.
You need a pencil and a page. Be in a quiet, peaceful area. Get atimer and set it for 10 minutes. Sketch the first thing that comes to mind. This exercise helps when you run out of ideas fo creating characters.
Draw all different shapes of eyes,noses,bodies,hair style.etc.. Experiment. Draw big eyes, small nose, short round body etc… Try out all different shapes until you create your perfect character