Browse through the Pharmacy College Application Service or the American Association of Pharmacy Colleges list of universities (see Resources) and requirements.
Verify that courses you are taking or have already taken will be accepted at the pharmacy school where you are applying. For example, an upper division "Biochemistry" course may not be accepted by some pharmacy schools because they only allow you to use an "Intro Biochemistry" as a prerequisite. Find course equivalencies by typing "[Pharmacy School Name] course equivalencies" into a search engine.
Contact the admissions department of each pharmacy school. Ask for a list of prerequisites. Ask to submit your current courses for review to see if they meet or will substitute for any prerequisites. Also request information on how to appeal for a class to be accepted by that institution.