-Fill light is your friend. EVERY one of these images would have benefited from additional/fill light, whether in the form of a simple reflector or an OCF;
-avoid shooting subjects, especially females, square to the camera, as you have done in the monochrome and the last two. This is what is referred to as "football shoulders" and makes the model look bigger and bulkier than she really is;
-black shirt and black jacket is too much black. Consider the location of the shoot and discuss compatible clothing choices ahead of time; and
-watch the details, especially the fly-away hair. If you're going to shoot out of doors, they're virtually unavoidable, BUT, you need to deal with them in post.