Have you used the powder before foundation technique?
If you've never tried it especially if you have an oily skin or get shiny T-zone almost immediately your makeup goes on then you should try using a powder before applying foundation, this technique simply mattifies the face keeping makeup product on for (way) longer than usual.
With oily skin, makeup go off easily while a few ladies prefer primer (usually the first thing to go on the skin before makeup application) not all primer gives that result and let's face it using a super expensive primer all day everyday under a makeup look is wasteful when there is a way to achieve a long lasting result without breaking the bank!
Setting the face and foundation with translucent powder (white/baby powder also work as great substitute) helps makeup stay on for longer and all you need do through the day is gently dab on the face.
Watch Dimma Umeh break this down in an easy tutorial or use this easy simple steps:
1. Dust white/translucent powder lightly all over the face (especially areas where you tend to get oilier i.e the T-zone)
2. Go on with primer or not and let sit
3. Apply makeup in the normal steps as you would
4. After applying foundation, dust on translucent/white powder all over the face again lightly and let sit
5. Bake and set undereye area and dust off excess powder
6. Continue with the rest of your makeup