I have to say that the hardest thing for me when I was an early childhood aide, when I was working in clinical settings, when I've gone into my mother's classroom, and now as a student teacher has been behavior management. I think I struggle with it because I am young and look much younger than I am, but also because I babysit quite frequently and like to be the kids' friend. I'm learning a lot right now about how to manage behavior and have come up with a chart that works wonders in my current setting.
It is a simple tally chart with spaces for credits and debits. Each student has their own row where their credits and debits are tracked. If they get 75 tallies, they get to bring a friend and have lunch with me in my classroom. When they are acting up, all I have to do is hover my pen over the debit column of their row and they usually get the hint right away. For a while, I was giving tons of tallies and not taking any away, and found that if every so often I give them a debit when they are being too crazy, it stops the off-task behavior for at least the next few days. Every Friday I total their tallies so they know where they fall and how many they need to earn to get lunch.
Here is an abbreviated version of the chart. You can download it below at my Teachers-Pay-Teachers site.