I know that everybody is having a hard time with choosing the right foundation. I'm even still searching for the right foundation shade myself.  A makeup foundation is basically one of the most essential tools for achieving a beautiful and radiant looking face.  It evens up skin color and lightly covers unwanted scars, blemishes, and pimples.  The sole purpose of a foundation is to even out your skin color.  Concealers are made to cover or conceal your scars, blemishes, pimples and other unwanted dark spots.

I'm not sure if there really is a perfect shade of foundation, but I've learned from various makeup artists, that they mix two different shades of  foundation to get the perfect shade they want.  As for me, if I use a foundation with a lighter shade, I just apply a slightly darker finishing powder to get the shade that is closest to my skin tone. (or the other way around)

I am not an expert but I did a little research. (sources from google.com)

Step 1: Recognize your skin type.

Normal Skin
- Complexion is even
- Surface is neither too oily nor too dry
- Face is supple with few lines, creases and wrinkles
- Face has few breakouts

Oily Skin
- Face has all over shine
- Shine happens quickly
- Pores are large and/or open
- Face suffers from frequent blemishes (blackheads and/or whiteheads)

Dry Skin
- Pores are undetectable
- Face looks and feels tight and dry
- Cheeks and/or chin are flaky and dry
- Face has lines and wrinkles around the eyes and mouth

Combination Skin
- has an oily T-Zone and dry elsewhere.

Sensitive Skin
- Face has distinct dry/red patches
- Skin is delicate or thin
- Face has sensitivity to products (burning or flushing)
- Face has Rosacea (Rosacea is a chronic, inflammatory skin condition which principally affects the face. Rosacea causes facial redness and produces small, red, pus-filled pustules (bumps). It is often mistaken for acne or eczema, or some other skin allergy.

Step 2:  Determine your skin undertone.

You must know whether you look good in Warm or Cool undertones.
Here's a simple trick I've learned from beauty gurus.
Look under your forearms, if your veins are mostly Green, that means you look good in foundations with  Warm undertones.  If your veins are mostly Blue, you will look good in foundations with Cool undertones. If it's combination of green and blue then you will look good in foundations with Olive undertone.

Warm undertone 
- these are for people who are dominantly yellow or has a golden skin tone.

Cool undertone
- these are for people who appears to have a pink or beige skin tone.

Olive undertone
-  these are for people who appears to have a slightly green-brown skin tone.