To help with expressions…
I love the movie The Secret of Kells for many reasons, but the animation is one of the the things that makes it a stand-out film.
This is a link to a model sheet for a character in The Secret of Kells named Brendan. The movie has a very clean design and it is easy to see what the animators are doing to create different emotions.
Notice the different emotions you get from having the eyelids go up, down, touch the pupil, etc. Try drawing him in a few different expressions…what is happening to the shapes?
This whole site has many amazing model sheets from different animated movies. I would recommend exploring the contents to see if there is a style that appeals to you.