Use the Training Modes
Use the training modes to hone your skills.
For example, you can use the training modes to practice flying in an X-Wing or A-Wing without getting killed repeatedly by superior players or feeling the pressure of a live match.
You can also use it to get more comfortable with heroes and villains and their special abilities. This way, when you do become Darth Vader, you'll have a clear understanding of his powers and limitations. Knowing how to properly use a character or vehicle will help you rack up experience.