
1. Cheat an eyeshadow crease by using the "dash and blend" trick.

It's basically connect the dots with eyeshadow. See the full tutorial at The Beauty Department.
Bonus trick: You can do the same thing with liquid liner and a cat eye.

Use a felt-tip liquid liner pen to dot your top lash line, then fill in the dots with liner and finish with a pointed cat eye flick.
You can watch the full tutorial from Deepicam here.
2. Make a DIY ~summer~ tinted moisturizer by mixing in 2-3 drops of foundation to your moisturizer with SPF.

This way, you don't have to buy a lighter coverage makeup for summer AND you'll get sun protection. Win-win.
3. Learn about brush volume, aka how vigorously or gently an eyeshadow brush will blend a pigment, by practicing your brush skills on a flat surface before you apply makeup onto your eyes.

This tutorial is a great place to start (and make sure you read the tips, don't just look at the pics).
4. Start drawing your under-eye concealer in a triangle instead of a crescent moon.

Read more about why here.
5. Get rid of eyeshadow fallout without messing up your makeup by using concealer and a Q-tip.

Once your eye makeup is done, apply a few small dabs of concealer over any eyeshadow that's fallen below your eyes and onto your face. Then, gently roll a Q-tip over the concealer to clean up the mess. If you need further coverage, you can apply a small amount of fresh foundation in the area with a brush.
Watch a full video tutorial on the technique here.
6. Use this face map to determine exactly where to apply bronzer, highlighter, and blush.

Get a more in-depth tutorial here.
7. Try using a makeup setting spray to keep your makeup from smudging, melting, or smearing all day long.

This NYX Matte Finish spray is $7.60. Just spritz it onto your face after you've done your makeup and then keep your hands off of your face.