A little super tip when retouching makeup

Wash your face before retouching!
If you feel that in the middle of the day, your makeup is worn out and your face is sweaty, do not remedy it by adding or retouching your powder/foundation/blush! (Retouching lipstick is okay though)
WASH your face before applying powder again. Think of it this way, you already feel that the makeup has worn off and your face is a little sweaty, chances are dirt has already stuck onto your face.