Fading Animation
This is the most simple animation, so we'll start with this one. First, you're going to need your color palette. Each color should fade back to the original letter color, but if you're doing a rainbow icon or using multiple colors, it doesn't have to.
You can add as many colors to your palette as you want, but the fewer the better if you're just getting started. You can see my palette for this icon on the right. If you find it helpful, make one of these palettes before you start your fade. The next step is to go letter to letter with black on your animation. First, copy the original slide and click "paste after current slide" several times (depending on how long your words are). Go back to the beginning and fill the first letter with black (or the first color on your palette, but for clarity's sake, I'll use the color palette I used for my sample animation). Then, go to the next frame and fill the next letter with black, and the next letter in the next frame, etc. until the end of the word. Click view animation and your icon should look something like the icon on the right.
Then, take the second-darkest color on your palatte and fill each white letter directly to the left of every black letter. (Don't forget to paste an extra blank slide at the end of your animation so you can fill the last letter of that slide with the slightly lighter color) Repeat this step for your other colors as well. That's it! Try it out, and once you're ready, go back and choose the next icon tutorial.