The way you handled Whitney's hair is doing real work, those tight curls have volume without going muddy, and the shine reads as wet-set, not just graphite shine. That's hard to pull off with colored pencil. The Karen portrait has a softness that fits her, but I'd look at the eyes again, the left one (her right) feels like it's tracking slightly different from the other, which can happen when we get too focused on rendering each feature separately instead of seeing the whole face as a gesture first. I still do that with florals sometimes, paint every petal before I've really nailed the tilt of the stem.

The Carpenter sketch, that shading around the eyes is working. I spent years trying to get pencil portrait likenesses to click and the thing that finally helped me was stepping back more often than felt natural, like every few minutes. Up close I'd lose the proportions completely. Hair texture is the part I still mess up constantly, so I can't offer much there except that your Whitney piece reads really well from a distance, which matters more than I used to think it did.