Let me start this off by saying that I like your art...
Now, with that being said there are still things that I don't like about you sets and that's why I am here, right?
Okay so, the first thing that caught my attention were the hands, they are very minimal and have almost, well, no detail to them at all, they are blocky and unattractive and don't match the set(s) at all. Try to round the edges to make them look more like fingers. you could also add palms and knuckles, fingernails, wrinkles, rings, etc.. etc... All of it comes down to detail which in todays market you really do need. you could also try to make hands that don't have fingers, not all sets will look good with fingers and you might need to come up with a better way for them to match the rest of the set.
Another thing that I noticed is that you tend to do a lot of the same things threw-out the entire set. for example, in the first set almost every texture has some kind of "band" wrapping around the entire texture. and in the second set you have circles everywhere always followed by some kind of a diamond. a little bit of variety can go a long way and can sometimes make or break a set or texture. but don't get my words mix up, I said a little! to much can clutter up and lead you in the wrong direction, they are called "minamilistic sets" for a reason.
Now lets talk about the colors.
everyone has there preference and some may like the two tone look. but in my opinion you need to go "gay pride" on some things to give them more life. would like to see a more colorful set form you. :P
on a positive note your mapping is good and you seem to have a good idea of how to make a set. but you need to put more detail into your work.
I am a fan of Bendovers textures and think that you could maybe get some idea of what I am talking about by looking at his work.
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http://bendover-za.deviantart.com/gallery/