My opinion only -
First photo: I do not like the color tint that it has. By trying to do monochrome/b&w, the dark jacket on a dark background doesn't make me want to focus upon her. My eyes are busy looking through the background trying to figure out if there is something I am supposed to find. With the pose she is using, her back is to the larger side of the frame (versus standing camera right side, looking left). Whether you cropped it this way or unintentional, her pinky is cut off. You have left a lot of head room which you can use to your advantage in a portrait. Move/zoom in tighter and have her fill up the frame more (since that is the intent).
Second one similar thoughts on the background. Although it is colorful, this is more of a snapshot in the park. A lot of business is going on behind her: should I look at the pink flowers, the orange thing, the lighter areas, the trees hanging down, etc. Move in or zoom to keep the distractions away from the intended subject (don't have the trees in the background grow out of her head though). You aren't shooting the park, you are shooting her. The pink flowers would make a good back drop and contrast in colors from what she is wearing. The pose is better albeit in the center of the shot. Focus seems off just a little.
If I wanted to improve the second shot, "I" would move approximately 3-4 feet to the right, lower myself to have the camera lens just a little above her and zoom in. This would eliminate the aforementioned items in the background, eliminate the dirt that is seen and you would have a much more pleasant portrait photo.
Keep shooting and keep asking.
Gart