How can I be a better swim teacher?

I worked at a summer camp last year teaching kids in grades 1-6. I'll be returning to the camp this summer to teach again, but I don't feel like I did a good job last year. I guess I did good enough for them to ask me back, but I want to really teach these kids a lot. We have half hour lessons with groups of 2-7 kids, all the same gender per group. We base the levels off of Red Cross levels, with some changes to groupings and names of stuff. I feel like they got kind of bored fast last time, and I need different types of activities to do with them.

For supplies, I have access to:

1. Noodles
2. Kick boards
3. Diving sticks
4. Dumbbell floats
5. Inflatable buoys

If anyone has any suggestions, that would be great. Also if you know any websites or resources I could use, that would also be cool.