Encouraging your child to participate in some group activities can be helpful as it allows them to practice social skills; such as compromising, taking turns, and compassion. Competitive sports or games where there are winners may also help them learn to lose with grace - I tell the kids, you play to win, however you have to accept the possibility of losing and be a good sport. No one likes to play with a sore sport or someone who cheats just to win. We also talk about recess being a time for fun and it isn't meant to be competitive such as when they play sports with their "team" outside of school. It is just as important to give them some "free" time. Don't fall into the trap of over committing your child. It is just as important they have to time to "free" play. That's where they truly learn how to get along with others.