HERE is a link to helping with MAC shades. It's really thorough and informative. Also, here are some basics for any foundation brought to you from Epinions.com (my comments/add ons are in red):
Consider Your Skin Type:
The first thing you need to consider when selecting a foundation is your skin type and the needs you have, like sensitive skin & allergies. Do you have oily, dry, combination or normal skin?
~Oily Skin – Make sure you select a foundation that is oil-free and controls oil and shine. Foundations with a matte or powder finish are very popular with people that have oily skin.
~Dry Skin – If you have dry skin, you need a foundation that has moisturizers in it. Dry skinned people have better results with a creamy foundation rather than a matte or powder finish makeup. These types of makeup can appear caked on dry skin.
~Combination Skin – If you have combination skin (like dry skin with oily T-zone) than you need a makeup that has moisturizers in it, but it’s oil-free and controls shine in your oily spots. There are many makeup choices for combination skin.
~Sensitive Skin – People with sensitive skin need to select a makeup especially for sensitive skin. Probably something that is oil-free, fragrance-free, non-comedogenic, and allergy tested for skin irritancy. Check makeup labels to be sure about these things before you purchase a foundation.
Consider Your Skin Color / Tone:
Selecting the perfect color foundation is SUCH an important part of buying makeup. If your foundation does not match the color of your face, hi, you won't look that great =). You need to be sure it's not too dark or light. I used to think it was impossible to find a makeup that was the “perfect” color, but I now know that there is a color match for every skin tone and color.
Normally all brands of makeup are grouped into something like “Ivory”, “Beige or Tan” and the “Natural or Neutral” colors. So you need to figure out what your skin coloring is. Ivory would be fair skinned, Beige or Tan would be darker skin or suntanned skin and Natural or Neutral would be darker than fair or pale skin, but not dark skin.
If you have ever looked at all the color selections available in foundations, you’ll notice that there are always several to choose from. Usually there will be several colors in the “Ivory” group and several colors in the “Beige” group. The reason there are so many to choose from in the same group is because everyone has different skin tones. You and your best friend may both have Ivory colored skin, but you may have different skin tones. Think about a medium colored Caucasian person (maybe part Indian), a light skinned African American person and an Asian or Oriental person…they all have about the same color skin, but obviously the skin tones are very different.
What are skin tones? Well, if you look carefully at the different colors in the “Ivory” or “Beige” groups, you will notice that some are very neutral or natural colored while others have a pink, yellow or peach tint to them. This is to coincide with different skin tones. My natural skin tone is a bit on the pink side, so I need a foundation with yellow or neutral tones in it to even out my skin tone. I would never purchase a foundation with a pink tone or else I’d look like a bottle of Pepto Bismol! LOL Make sense? So you need to be sure about what the color of your skin is and what skin tone you favor before selecting a foundation.
When trying to decide on a specific foundation color, once you have determined the above criteria for your needs, you should then test the foundation on your skin to make sure that it is a match. I have seen so many people test makeup on their hands, but your hands are not always the color of your face. The best place to test a makeup is on your neck. The neck is where your makeup will meet your natural skin color, and it has to be the perfect color in order for it to blend smoothly and evenly, not leaving a noticeable line. So test the makeup on your neck or bottom of your face and blend it in well. The way you can tell if the color is just right is if it blends into your skin so well that you cannot even tell where you applied it. If this is the case, then you have found the perfect color for you.
Consider Your Climate and Environment:
The above criteria are definitely the most important in selecting a foundation, but you should also think about where you live and your climate, your everyday environment and your lifestyle. If you work in an office environment, you can use just about any type of makeup, but if you work outdoors or in very hot and humid conditions, you may need to be careful about your foundation selection. Some foundations do not hold up well in high humidity climates or very hot weather. Also take into consideration if you sweat and perspire a lot while wearing your makeup. There are special makeup formulas for this type lifestyle.
If you are outdoors a lot while wearing your makeup, you need to consider a foundation with SPF in it. Also think about whether or not you may need a foundation that is waterproof and/or sweat-proof. If you sweat or get wet, you don’t want your makeup to run off your face and leave it unprotected from the sun, or look like an idiot with half your face done...I'm just sayin =).
If you live in a very cold environment, and your skin tends to dry out in cold weather, you should make sure you select a makeup with moisturizers in it. If you have oily skin and the cold weather still dries you out somewhat, you can select a foundation that's oil-free but still has other moisturizers in it.
Consider the Look You Want to Have While Wearing Makeup:
There are so many different finishes in foundations today, so you need to decide what works best for you and your needs before selecting a foundation. This criterion may also be determined by your skin type needs mentioned above.
~Sheer or Natural Finish – This is the foundation for those natural beauties and people that do not need much coverage due to smooth, clear, even skin. Just for your information, I despise these people ;-) (just kidding) If you are not a “makeup person” but you want a foundation that is light and sheer, you should go with this type of finish. These foundations are usually in liquid form and are almost the consistency of pure water.
~Medium Coverage – These foundations are thicker in consistency and provide some coverage for people with blemishes, discolorations or just uneven skin tones. They go on thicker and can be purchased in liquid form or compact form (like creams, sticks or cream to powder).
~Matte Finish – These foundations are typically for those with oily skin. A matte finish is great for helping to control oily shine and breakthrough shine later. Matte finish makeup is also available in several forms (liquid, creams, cream to powder etc.) Matte finish makeup usually has a good bit of coverage to offer.
~Powder Finish – These foundations go on creamy and dry with a powder finish. These are wonderful for those with oily skin or combination skin because they tend to be thicker and the powder helps with shine. This type of foundation can be used by anyone, however, if you have dry skin, you will definitely have to apply a good moisturizer first.
Getting the Most Out of Your Foundation:
Selecting the best foundation for your skin care needs and wants is important, but if you have the best makeup in the world it won’t matter if you don’t prepare your face first. You should always use a good cleanser, toner and moisturizer before applying your foundation. Check out the skin care post link for more info on this topic!!!! It's pretty thorough.
Compliment Your Foundation:
Consider using concealer and/or powder along with your foundation for a completed look. Concealers can be purchased in different tones and forms (sticks, pencils or creams) and they are very easy to apply. I personally LOVE the camo palette from MakeUp Forever!!!! Concealers are great for blemishes or discolorations that are not totally hidden by foundation alone. I will be posting my new daily face routine soon!!! Powders are great for setting your foundation. The two work together to give you the ultimate coverage and duration. Powders also come in coinciding color tones and you can get them in loose or pressed form. If you are using a cream to powder foundation, you may not need to apply a separate powder unless you have very oily skin.
Hope that helps Ladies. Now, go get your founDATION on!!!!! =)