Your concealer should always be a shade lighter than your foundation.
Extra Coverage - Pat and blend concealer and let dry, pat and blend on a second coat and let dry, then powder.
Major Cover-ups - Apply concealer twice, both before and after foundation.
Softer Facial Lines - Apply concealer directly on lines and over foundation. Pat and blend, let dry, pat and blend again and then powder.
Eye shadow Base - Pat and blend concealer on upper eyelid to create a holding base. Apply powder on top of concealer before applying eye shadow.
Spot Check - After all makeup is applied, dot additional concealer over any visible imperfections and then set with powder