Portraiture is certainly not for the faint at heart -- and you've managed to really capture some good expressions here.
I agree with Naris -- there are some distracting elements in each work, though. I also thought that some of the value work wasn't pushed hard enough -- really dark darks and really light lights would help mitigate some of the "flatness" in areas and make these pieces pop. I think it's the flatness that's causing various elements to compete too strongly with the figure in each.
Here's a quick tweaking of your paintings I did in photoshop -- mostly just bumping the contrast up considerably:
I know the skin tones get a little squirrelly, but notice how certain areas have more depth now -- in particular, the patch of hair over her ear, for example.
And the second one:
Again, disregard the color shift for the most part, and instead concentrate on how the contrast enhances the "pop" of the image. One other thing I find visually distracting about "Tatiana" is the strong horizontal of red on the bottom of her clothing. It's abrupt, and my focus tends to get hung up there. Perhaps a little more value work in that area [perhaps adding a few folds?] would help to break up the space in a more interesting manner.
Hope that helps.