Here are some good yet fun ways to keep order in a classroom setting. I have found that when kids start getting restless, or are getting distracted from the lesson if I do one or two of these things it helps bring their attention back on me.
I learned these simple finger commands from IBLP.
When you hold up one finger that means to sit up straight.
So to practice this have the kids slouch down and look really sloppy. Then tell them as soon as you hold up your finger to sit up as straight and tall as they can.
Holding up two fingers means to stop talking, stop laughing, or stop whispering.
Have the kids start talking to each other and making noise while still keeping an eye on you so when you hold up two fingers they instantly get quiet!
Then number three means to smile with at least three teeth showing.
So, have the kids make really sad faces, then when you hold up three fingers every face should have a cheery smile. :)
One more thing that is hard especially when you have a younger class is to keep their eyes on you.
So one thing that helps with that is to train them that when you say "Eyeballs!" the kids respond with saying, "Click!" and their eyes on you! Kids seem to think this is really fun and it's something you can just add in the middle of whatever you are teaching to get their attention back!
Hope these are helpful! :)