I used to do a lot of tracing in Jr. High. Mostly Nintendo art, but not so much pixel art. I'm talking about box art and posters. I also got pretty good at just looking at existing art and drawing what I saw, which is really just tracing at a distance.
These are 32x32 icons, in the style of the Classic Mac. See: Steve Icon
I'm using Pixen to do these icons. First, I take the full-size picture and re-size it to 32x32, so I have a full-color reference. Then I put dots on top of it. Sometimes it works better than others.
It's not as easy as it may look. Just one dot can make a huge difference, especially since there are only 1024 dots to work with.