Is there a set amount of smilies/frownies you should give in a day? Do you give a smilie/frownie each time they do what you want them to do? I don't want to over reward. Also, when should they win for the first time if I am starting the scoreboard on the first day of school?

There isn't really any set amount. Generally, you will have a lot more marks in the first few days or weeks as the kids are getting used to the system. As time goes by you can make them work a little harder to earn a mark.

The main rule to keep in mind is +/- 3: Make sure that they do not get more than three ahead of behind you. If you over or under reward then they won't be as attentive to the game.

You don't necessarily have to let them win the first day. If they win or lose make sure it is by a narrow margin. The closer they came the harder they will usually work the next time to win. Make sure you keep the whole thing positive. This way they see it as a friendly competition.

For Example:

You: "Wow! That was great! You only lost be one point. One point! That was so close. I'll bet you can win tomorrow!"