Animators are story tellers. Every animation should have an idea behind it, one that tells a story.
Junior animators focus on learning technique - and technique is very important. But it is also important to think carefully about the story behind your shot.
Who is your character, and why are they doing what they are doing? What is the scene about? What do they want, and what do they fear? These things are important because if your shots forms part of an interesting story, it will be much more interesting to watch.