Try to make small drawings, if it’s goig to be 3D you’ll be abl to zoom in as much as you wish without loosing quality, olny use simple colors no textures…. texturing you will do in pro animator…
The best tool for creating good shapes is the pen tool. to close a path, just click over the first point you have created.
If you have text on you project after finish it, right click it and choose “create outlines”…
big hugs from Brazil