on the first shot, the pose seems mixed up. Like SHE should be the one leaning in to him, and HE should have his arm around her.... some of these could have benefited from fill flash or a reflector to get more light into their eyes as well.
On the single girl in the field shot, either get up higher or direct her nose to be parallel to the ground. You will find some people ALWAYS tilt their heads up slightly when posing, and that closes up their eyes slightly and gives us an unflattering view of their nostrils. She is doing that in this shot and you need to notice and correct when people do this, unless it was intentional for some reason. Also, in that shot, her other arm would look nicer bent slightly. Rule of thumb, meant to be broken situationally is that if it has a joint, bend it. Fingers, arms, knees etc.
On that shot in the grass, the foreground grass should have been swept away and held down with a shoe or something, just the stuff crowding her chest area. Even though she might be a bit taller than he, I'd have sat him on a jacket or something or had her schooch down a bit to make him slightly higher than she is. Then directed him to bring his face out from hiding behind her. Nice job on keeping their noses parallel to each other though and nice expressions. Great start though, keep at it!