Image one: crop out all the stuff on the right hand side that is a waste of space. As composed, would work best as a square.
Image two: crop to 4x5 ratio, cropping out the wasted space to the left hand side, and a bit of the grass
Image three: OK
Image four: crop to a 4x5 ratio, getting rid of the stuff on the left and right hand sides
Image five: should be a vertical shot showing the entire kid plus some of the taller person's hand.
Image six: crop to a 4x5 ratio cropping out the wasted space at the top and the really bad looking back at the right of the picture.
Image seven: your best shot, but... A) it's crooked, leaning to the right. B) it's not cropped nearly tight enough. C) you have an f/2.8 lens, so use it at f/2.8 when you have a distracting background to get rid of stuff like the cars.