Think back to when you were 5,6,7,8,9 or even 10 years old. You probably had a wild imagination, always looking for something to do, couldn't sit still, and a short attention span. Now imagine being that 6 year old self at a swim lesson/practice where no one explains or shows you what to do but says "ok streamline kick, GO!" and your off, haven't learned anything in those 2 seconds and no one is guiding you down the pool or helping you stay afloat. You don't know what streamline is but your doing everything in your power to stay on top of the water. As you can imagine, this is not the best or most effective way to teach kids to swim, regardless of whether their parents have put them on the swim team and you assume they know what your talking about or not.
When working with the 6 and unders it is important for the coach to be in the water at all times and you should always have 1 coach per 5 kids. Now pay attention and remember this. The amount of time (in seconds) you have to explain something to the kids corresponds directly with how old they are, i.e. if they are 6 years old you have 6 seconds to explain or you lose their attention. That goes for everyone up through your oldest swimmer.
With all that said it's time to make these practices fun! I have found that kids learn best when you explain the strokes in a way they understand. When talking about freestyle have them cup their hands then imagine that the water is their favorite kind of ice cream and their hands are the scoopers. You can take it further and ask them what ice cream they'll be scooping, they get excited to share their favorite ice cream flavors with you.
Breaststroke - With the older kids you can have them lay on the side of the pool with their shoulders over the edge of the wall and walk them through the breaststroke pull. This way they get the feeling of where the hands should stop before shooting forward to streamline. With the little kids you can do the same thing but give them something to focus on while swimming. You can have them make the bowl that the ice cream they scoop during freestyle goes in. OR, my favorite you have them make their favorite pizza and (when their hands shoot forward) serve it to their friends. It gives them something to think about while swimming, and makes the stroke more fun and the length of the pool, which seems so long for the younger ones, a little more fun :)