A teenage girl struggles to deal with everyday life on a planet populated by aliens.

The logline sets up a situation for a plot -- but it doesn't set up a plot. ?Check out "Training" at the top of the web page for guidelines for writing a logline that describes a plot.

"Struggles" is too vague. Include an inciting incident, and then create a conflict from that incident. Perhaps use her arriving on this planet as the incident: When she lands on an alien planet, a teenage girl....