There's a couple of things that work really well in our primary....
The first one is our reverence song. I've noticed a huge difference when the children come in and leave. We sing the same song the entire month, so they will learn it. It is sung as the junior primary leaves and the senior primary is coming in. Then we sing it again when the senior primary leaves. We remind them to walk reverently in the halls and enter reverently into the primary room.
The second thing is my testimony. Sometimes things get a little goofy up there! I love to make them laugh and have a good time. But, I always end singing time with my testimony to the children. Sometimes it is as simple as "I want you to know your Heavenly Father loves you and I know the church is true." A member of the presidency mentioned it last week and it made me feel good, knowing that it is somehow making an impact.
And, I've started a new thing. When it is time for singing time, I do a couple of wiggle songs. I've done this for a few weeks now and the kids really respond. I need to wiggle after sitting in sacrament for 70 minutes! I always end the "wiggle time" with a slow-down-and-fold-your-arms song. I realized that they need it when I started giving my own children "decompression" time after school before starting homework. Plus, it gets the blood flowing and the brain active!
Anyway, just a few of the things that are working here!