Even Out Skin Tone
Step 1: Apply foundation over the whole face, then treat the dark patches with a full-coverage concealer. Products with sufficient pigment for this purpose will have a thick consistency and will usually be labeled as providing medium, full, or heavy coverage. Warm the concealer in the palm of your hand to make it creamier and easier to apply, then blend it over the trouble zones using a dry sponge (a damp sponge will dilute the pigment too much).
Step 2: Setting the makeup with powder will help it last.
RS picks: L'Oréal Paris True Match Super-Blendable Concealer ($9.50 at drugstores); Dermablend Quick-Fix Concealer ($24, dermablend.com).