p.1 #2 · post editing : DDP+lightroom... my first time
My 2 cents:
As much as i love photoshop, I would suggest that learning to light your subject properly is more important than good post work. If you notice, most of the shots have fantastic lighting and only a few seem heavily post-processed.
If you look closely at the shots in the link you posted, almost none of them have all black shadows with no detail, especially the subjects. There is detail corner to corner across the image.
Now imagine you had been able to light up your shot and provide detail to all areas where there are none, im sure it would have improved it far more than anyone could in post.
p.1 #9 · post editing : DDP+lightroom... my first time
Really like your shots! I do all my post-processing in Lightroom, so feel free to ask more specific questions if you want...
It seems to me that the first shot has an imbalance: The flash is a bit too harsh and the background is a bit too dark/far away. I would try to tone down the flash (or diffuse it a bit) and place a colorful background right behind the subject.
The other two shots are much better in both respects, but the post-processing seems a bit too extreme for my taste. I would suggest less saturation and less sharpening to get a more natural feel. I also prefer to use other software for sharpening, as I don't like the way Lightroom does it...
Anyway, I hope that my long message helped. And, of course, if you check out my photos and decide you don't like the way they look, feel free to disregard everything I just said.