Before I talk about various different foundations, you need to know about finding your shade. This isn't as easy as choosing between light and dark. Even drug store brands are beginning to realise that foundations need to have different undertones. What are undertones? They're essentially the colour direction in which the colour of your skin leans. Whilst your skin may lighten and darken, your undertones remain the same. Once you figure out your undertone, finding a foundation that matches you correctly will be far easier. We can divide undertone types into four categories:
Your skin leans more towards pink. You tend to look better in blues and purples, and silver jewellery. The veins on your arms look more blue.
Your skin looks more yellow or golden. Yellows, reds, and oranges look better on you, as does gold jewellery. The veins in your arms look more green. It's also important to note here, that not all Asians are warm toned. It is possible to have yellower skin, but with cool undertones. Follow your instinct, and look at which colours you look best in. People usually instinctively chose colours to wear which match their undertones.
If you don't seem to lean towards pink or yellow, you probably have neutral undertones. You can get away with wearing most colours. The veins in your arms look both blue and green (or somewhere in the middle).
Olive can be a tricky undertone to spot. It's often confused for yellow undertones. However, people with olive skin tones can have more than of a greenish tinge to their skin, particularly if they are compared to someone with warm undertones. Many brands still do not carry olive toned foundations (check out Illamasqua's skin base foundation if you're looking for an olive-toned foundation)
*A note on MAC foundations
For some reason, MAC foundations work in the opposite way; Their NW (neutral warm) foundations are actually for people with pink (or cool if you're every make up brand!) undertones. Their NC (neutral cool) are therefore for people with yellow (warm) undertones. I honestly don't know why this is, and I've yet to hear of another brand who does it this way, but it's something to bare in mind if you're shopping for foundations at a MAC counter.