Metrics are your grade point average (GPA) and entrance exam scores. Performance in your coursework and entrance exams are strong predictors of success in graduate professional programs.
Some programs will focus on your overall GPA or discipline specific GPA, for example biology, chemistry, physics and sometimes math as well. Most professional programs require an entrance exam, such as the GRE, PCAT, OAT, DAT, MCAT, etc., these are offered at various times throughout the year and are specific to each type of exam.
Research the required and recommended coursework for programs that interest you. Know which exams are required for all schools you plan to apply. Know the general schedule for these exams.