Most of your stuff looks really good but sometimes I see this contrast thing that you over do. For an example; The last portrait has a lot of harsh colors to it and very hard highlight. She looks very metallic. This is something that you do a lot I feel so that would be something to tackle.
Try getting the light on the skin as good as possible and transfer what you learn to your personal work. Calm the whites and the use of bright spots, you only want to use those where the light hits more intense, else it will wash it out completely.
The first portrait looked a lot better though, that's what it should look like. Try to remember those things when you do your own stuff too.
Agree with Loathsome there. I always feel it too, but never find the right words to say it (cuz i don't really know what the exact problem is). The feeling i get from your works from imagination are something like "monochromatic with specks of colors everywhere", it sounds confusing, i know, that's why i didn't say it. So it's a good thing you have Loathsome there, to crit you. I guess he made his point clearly And yeah, i don't see the problem in the previous update too (the man with a turban on), so i think that's the thing to apply in your future works that come from imagination.
Anyway, i like and am enjoying your studies lately. You're doing good, mate. Keep going