Ahhh! Thank you one million times over for such an detailed response. I am set on fire with motivation!

I agree 100% with the critiques. I am creating a list of all the tips and suggestions you have given me, so that I'll be sure to use them! Thank you again for such an amazing response, I am so humbled that you even made an edit! It really shows the issues at hand. ba dum tss!

There are some techniques that you've used in the edit and in your own projects that I can't wait to master. Specifically, learning things about saturation, hue, anti-aliasing, the difference in knowing when to use certain outlining techniques, ect.

I will detail this more in my response on the candle! Thanks again for everything! The notes, the criticism, and the inspiration!

Great work on this. A few notes if you don't mind:

The minimal shading is fine, but if you're going to go that route you may want to choose a darker tone for the color that takes up the majority of the hand. It doesn't have to be that much darker, it's just something to lower the overall brightness of the piece.

In addition, the color you're using for your outline is fine on light backgrounds, but the darker the background gets, the less good it does. Usually, if you're going to make a transparent image, you'd want to draw the image on a neutral gray background (120 luminosity) and make it so the colors pop on that background; that'll usually indicate that they look good on most. In general, darker is better for outlines in this context, but that doesn't mean that a black outline is the best. A very dark, saturated red could make this picture really pop.

By the way, since this image is transparent, there are technically 5 colors (transparency counts as a color). The pink on the nail is very difficult to see, but if the skin tone is a bit darker, that should actually help that.

It's clear you're dedicated to this craft and more than willing to make friends and learn. The spirit you bring to this website is lovely, so I hope my criticism doesn't discourage you. 

Here is an edit I made where I haven't changed any of the clusters (except on the nail), only the colors. It's probably best that you don't continue to use sel-out on these pictures; with a colored background, it can work, but it's tough to pull off on a transparent one.