It is always best to stick with powder foundations when you have skin is on the oily side. These foundations will soak up oil and leave your skin. If you are prone to oily skin, it is best to avoid liquid foundations, since they tend to make the skin worse. Use a sponge to put sunscreen on your sunscreen. It will also allow for deeper penetration.
People who have very sensitive skin ought to use products that are mild and gentle. You need to find products that are free of perfumes, dyes and other chemicals, as they will irritate skin and could make a rash show up or a breakout.