That isn't necessarily ALL of what I said, if you read over my post.
And in fact, that's not ALL of what everyone else said, either. Dark Moonlight said that the pixel overs' outlines look jagged and the shading looks choppy. GS mentioned that the fusions look really choppy; despite both of them not exactly mentioning how you could change them. Hofromwever, I see where they're coming from from that.
And "tutorials from other sites" aren't just...blah. Look at the right ones, and they can really help you.
Anyways, I will admit that I did lack in giving crit, so I'll do that now, since I have time to.
The recolors look fine, but try making your own color schemes next time. It's not necessarily THE most important bit of recoloring, but it's nice to know about color schemes when making your own original creations, such as fakemon.
And if you're unsure about how color scheming works, I found this great tutorial for it on DeviantART not too long ago.
Since, after all, it can be a bit tricky to think up original color schemes that also look aesthetically pleasing. Just in general. Because, let's all face it: colors can and will symbolize several things.
As goes for the fusions, I can see you've "mastered the whole copying and pasting deal." Now, you need to start editing the parts on there on your own, because, let's face it: copying + pasting without really editing anything can look not only incredibly choppy, but also anatomically incorrect. For example, the right (our right) wing on the Flygon/Salamence looks like its bending back quite far...thus, how would our Flygon-friend be able to actually hover like the base sprite shows? He'd probably be flapping around quite awkwardly, if anything.
You could probably practice with "custom editing" by editing original sprites to give them added features and whatnot. Like...for instance, adding a scarf to Bayleef's neck or something. The possibilities are endless, but don't get too carried away until you've "conquered" basic editing.
Infernos: nothing to really say here, since this is just a form of pillow shading. It doesn't really have any artistic value...besides just trying to look visually pleasing.
Pillow shades: same as above applies here. However, when you start making customs and shading and whatnot...don't ever use pillow shading. Make sure there's actually a noticeable light source, because adding pillowed shading to everyday pixel art (and, at times, just art in general) is a mistake that beginners will tend to make. Sometimes. However, I think the biggest mistake is just when people shade with no dimension, like the surface was made out of a sheet of paper.
Pixel Overs: now, the lineart isn't actually that bad, just jagged here and there. And the shading looks incredibly bland on the first few, unless you were solely trying to cel-shade. But...even at that, you'd still need some work to do.
To be honest, I really don't know if I should say much about these. I think you should either A: use a new lightsource to the pixel overs rather than attempting to mimic the original, or B: try just making your own custom pixel art.
The Flareon's shadow-shade looks incredibly close to the outline color, by the way. It contrasts way too much with the main color, and too little with the outline color.
I've given my input for the icon recolors, already. In order for them to be actual revamps, you need to start by also reshading and editing the entire icons itself based on what style/generation you're trying to revamp it to.