Using primer and also a pressed powder help to set makeup. It also depends on what foundation you're using. You might just not have enough coverage to begin with.

Most foundations no matter what they promise don't last for more than a few hours without fading or streaking. I'd recommend some powder (loose or compressed) over your foundation, for me anyway it keeps my makeup on all day with no touch ups and it controls shine. One foundation i tried and stayed on all day was estee lauder double wear liquid , it's amazing and there powder is good too i am currently using that and i love the look over my foundation.

You skin is absorbing or "eating" your make-up. Make sure you cleanse and tone before applying the make up. Use a primer and then try and purchase a color stay foundation. they make them specifically for this reason. then set with a translucent powder.

Try using a foundation primer. One of my favorites is Laura Gellar "Spackle". Make sure your foundation is suitable for your skin type and dust some translucent powder over your foundation for more staying power. If your skin is oily, try a foundation such as Estee Lauder Double Wear.....it literally stays on all day!

You must have very oily skin. You need to start with clean/toned skin. You can buy Witch Hazel from the drugstore for a few bucks & use that to tone your skin. Then apply two thin layers of primer, and always set your makeup with powder.

It might be because they're not good quality, or you need something to set it. When I apply wet foundation I usually powder it with foundation so it sets. I also use water proof mascara and liners and stuff because I have oily and sweaty skin so that usually helps.
I think try applying a base like some creams then put foundation over that.

Hope I've helped!! :)

because they might not be of good quality or you do not wear a base?