Jinx? Stands for Jinx! Durr.
Alright, first we'll talk about the icons. The whites are a little too bright. All the colors in an icons are supposed to be balanced. If a single color overpowers other colors, it pretty much spells the doom of the icon. I'm not saying those icons are bad, no. In fact, compared to what I used to make with similar amount of experience as you, you're doing much better. But they can be made much better if you learn to balance all the colors. Maybe, instead of focusing only on the whites and trying to bring out the contrast, try using selective colors? They work really well. And if you find that strengthening specific colors in the icon messes the balance and makes it all weird, try gradient maps.
I mean, for example, you're working on a stock which comprises of a lot of red. And then you've placed a blue bookeh over it. Now you went on increasing the intensity of both red and blue. You'll find that the outcome doesn't look as good as it should look because there is a lack of flow between the two colors due to overwhelming disparity. Gradient maps might help you in those cases. Try to avoid text in icons as well. The text in your first icon, although not bad, doesn't help the icon, imo. Text placement, if it works, really looks good. But if it doesn't, well, it might end up hurting the icon by making it look a little too busy. Not the case with your icons, but yeah, just worth putting it out there.
Oh, and in case you're using a light color as a background, you can use a little bit of the burn tool set to 'highlights'. That'll be able to burn some corners and will generally help you out with the lighting in the icon. Something like this and this. See the dark corners? Yeah, those have been done using the burn tool. Without those, I dunno if those two tags would look as decent as they look as of now. :p
I guess that's enough for icons. Moving on to tags, well, for starters, you ought to work on your depth. And the effects. And a little bit on lighting as well. It'll probably take a lot of time if I go tag by tag, but lemme see how much I can write without tiring myself.
Well, this work here basically share the same problem as the icon. Lack of balance in the coloring department. But since it is a tag, it has another problem going. Lack of focus. You've got three. You're supposed to have only one. You may have more than one stock in a tag, but there's a specific part of the tag that should make other peoples' eyes automatically get directed towards it. That's the focus. It generally tends to be sharper than other stuff in the tag. Or the other stuff is supposed to be blurred. None of it here. So yes, it is a bit flat. :[
I'm not really gonna comment on the second one since it looks like all you did was paste the render on a background and add some text to it.
This one suffers from lack of depth and lighting. And non-variety of effects. All the effects are in the background and are similar in structure. You're supposed to add some variety since, you know, variety is the spice of life. :p Anyway, yeah, bring moar variety! You need moar effects going on in it. Plus, try to use multiple colors. This tag here basically comprises of black and yellow - monotonous. Monotone isn't bad in every case. But you need to have depth so that it looks good even if it is monotone. But this work here lacks depth owing to lack of sharpening, blurring and appropriate lighting.
Out of all your works, I like the chun-li tag the most. It can be made much better by a few tweaks very easily. You can burn up some corners, give it a light source, make the stock less uhh..out of proportions? Chun-li looks weird here, for some reason. Anyway, yeah, apart from that, you have the effects going in the background. Just add some foreground effects, blur some background ones and you'll probably be looking at a much better looking tag. At least when seen from my eyes. :p
Hopefully, that was of some help. Seriously, tell me if I was too harsh, okay? I really wanna see you improve, you know. ;_;