If you are going to an event and are looking to give yourself a new look with makeup, then the first and foremost important step in getting the desire outcome is the selection of right foundation for yourself.
The first thing you need to know before selecting a foundation for your skin is to know your skin type. If you have an oily skin, then you should apply the powder form foundation on your skin because it will merge nicely into your face skin and will give you a medium combination skin for applying makeup.
If you are an individual with dry skin, then you should select an oily foundation so that it can easily dissolve into your skin and in result will give you a medium skin to apply makeup.
The next step is to match the foundation with your skin color. If you have a dark complexion, then you should apply a lighter tone to your skin and on the other hand if your skin color is fair, then you should apply it accordingly to your facial color.
The main objective of the foundation is to make your face look perfect and to hide the imperfections. In last I would personally suggest you to always apply a water proof based foundation because it will give you a lasting result.