Looks like you are getting the typical Canon "yellow" tones in your images, either a custom WB or shoot in RAW to make up for those (or dig really deep into the manual and set the color parameters on the camera to tone them down). With this group of images and some of the others you've posted I would like to see things cropped in a bit tighter. Fill the frame with the subjects, I know you like the setting, but the image is about the people in it. YOu can tighten some of these up buy turning the kids at angles instead of squatred up straight on, this also will get them closer together.
Lastly, watch out for hats, they leave shadows on faces (also hiding the eyes) that are not very pleasing, be ready to deal with those either at the time of shooting (a reflector can work well) or in post processing.
Also, if you can leave exif info attached to images that sometimes helps with giving some helpful ideas. The same thing with allowing others to edit images you post, that can be a huge learning tool.