Some tips:
Make sure everyone who uses these toys can swim well.
Have a person or life guard on hand.
Buy top quality products to ensure hours of fun and durability.
Wear sun screen, the water reflects the sun more intensely
Let the younger one's or those that don't swim well wear life jackets
Be respectful and aware of other people or boaters
If a child is shivering then they are cold and it can lead to hypothermia
Drink plenty of water- you can actually be dehydrated on very hot days in the water
Know your water;
is the safe to swim in - water quality
are there sharks or other aquatic animals to be weary of
How shallow is the water?