When you are learning to apply and use makeup you make a lot of mistakes. You apply the wrong color to wrong area, you make yourself look a raccoon. Those mistakes should not continue into adulthood.
When you are applying you makeup the best rule of thumb is less is more. Never, ever make you eyes look so dark you look like any animal. Makeup should be used to enhance your features and let your real beauty shine so let it do its job. Remember that if you are making one part of your face look dramatic, like having a smoky eye or a red lip, you should go neutral everywhere else.
Always, always, always match your skin tone to your councillor. There is nothing worse than looking at someone who has councillor two shades two dark for their skin tone and their head looks like it is a different color than their body. Not only will you look ridiculous but you will bring more attention to the flaws that you were trying to hide. Also, make sure that you are not caking on councillor and power. You face should look fresh not like plaster. If you are having a bad skin week, applying a large amount of makeup will only make it worse.
Do not match your eyeshadow to your top. While you may have done this in middle school, you should not do it later in life. You will end up looking like a clown. Nuetrals are great choice when picking out eye makeup shades.