What are they looking for?
Freshman applicants to the University of California are evaluated based on 14 characteristics. Importantly, each of the nine undergraduate campuses gives different amounts of weight to these factors. If you're planning to apply, look at the selection process used by each individual campus. It will not only shed light on how your application will stack up at each school, but will also give you insight into the differences in values and culture between them.
The factors considered are:
GPA in a-g courses
Selection of and performance in other academic courses
Selection of and performance in honors, AP, IB, college courses
Rank in top 9% of your class
Senior year course selection
Academic performance relative to educational opportunities in your high school
Outstanding performance in specific subject areas
Outstanding work in special academic projects
Recent, marked improvement in academic performance
Special talents, skills, leadership potential
Completion of special projects undertaken in the context of your high school curriculum or for special school events/programs.
Academic accomplishments in light of difficult life experiences or special circumstances
Location of your high school and residence