Spot-on comments above! Focus is absolutely critical in portraiture, and if nothing else is in focus, the eyes MUST be. Use single-point AF with that point over the near eye, and ensure that your DoF is sufficient to get everything you want sharply focused (I dislike OOF elements in faces, but that's a personal thing). When it comes to cropping, avoid cropping the torso, and while it is considered acceptable to crop limbs, it should always be done boldly, and never at/near/through a joint, and never crop off "bits" that is, toes, finger-tips, etc. If you're shooting ambient light images, consider bringing a reflector along to add a little fill and direct some light into the subject's eyes. #3 is a great image, but would be even better with a small catchlight.