How do i landscape my very small overgrown backyard?

Question:we have a 30'X15' rectangular backyard overgrown with plants vines and shrubbery along the back wall of the house and security wall ( which surrounds the mobile home park ) Grass in the middle and overgrown plant life on all 4 sides. What do I pull out? What do I leave. We have a tripple wide mobile home (2000 sq ft) and a private yard we are trying to turn into useable space so we may sell the home and move out of state. We live in a large Senior park in Carson Ca.
Thanks so much
Chettar

Answers:
Any vines/shrubs that give an ugly look to the yard or gives a sense of clutter should be removed to get better overall appeal.