My almost 9 year old daughter is big for her age and has always been very strong. She is well behaved and very responsible but she doesn't realize that things she does can physically hurt her friends. She seems to have problems keeping her hands to herself. When she is excited about something she will often pick up one of her friends clear off the ground. She is athletic and competitive and doesn't like to lose. She fights constantly with her younger brother (17 months younger) and I fear that she will hurt him someday because she is considerably larger than he is. How do I teach her to be more gentle and less excitable?