How can I prep my skin before putting on makeup so I don't get pimples?

See below. Clogged pores contribute to acne. Wash & dry your face prior to applying skin care products. Make sure all products applied to your face (including makeup, moisturizers, sunscreens, etc) are oil-free & non-comedogenic (doesn't clog pores in most people). Always remove all makeup before going to bed.
Skin care. Many bellevue that a good basic facial wash with a non-comedogenic, fragrance free, hypoallergenic cleanser (i.e., cetaphil daily facial) may help. However the makeup itself can cause pimples so change it frequently to prevent colonization and consider mineral makeups that generally do not promote bacterial growth.