A good trick is to take 5 minutes a day to try and draw something. Which means each day try to think of something and draw it within 5 minutes. Doing these quick drawings/graphics will help to keep you sharp and creative.
In fact, some professional artists do this more than once per day. Except they usually sketch it out on paper and throw it away afterwards. You're not supposed to keep that artwork because it makes you stay in that same style and doesn't allow you to grow as an artist.
You should go out of your way to try and do different styles of art just to get experience in different things. If you're always drawing a certain way then all of your work will look the same. You want to be able to work in such a way that you could make two different graphics and nobody could tell they were by the same person.
