The emphasis at the U-10 level should be on teaching them to enjoy the game. Practices should consist almost entirely of fun activities that will help the players learn technique while playing games. Time should be spent on demonstrating and practicing technique, then games should be played that stress the particular technique. Ideally the kids should be playing and having fun with various games making use of the soccer ball, and maybe not even realizing they're learning how to play the game. Kids at this age want to have fun.
Emphasis is still on technique and fun, but more complex tactics can be introduced.
Use primarily 3v3 to teach movement and support, but also up to 7v7 to help players learn to see more around them, and begin to understand more complex situations. 11v11 should only be taught sufficient to allow team to be competitive. Begin to incorporate increasing pressure so that players will start to learn to perform technique and tactics under limits of space and time. Girls may tend to become team oriented earlier than boys. Many players will have decided by this age that soccer will be their number one sport, or even their only sport.