Organize stations by ability. Color code ability groups (i.e. Green-Beginner; Blue-Rookie, etc.). No one should be standing around while you arrange things. Keep everyone busy.
Keep athletes informed of changes in schedule or activities.
Introduce athletes to one another, and orient them to the instructional setting.
Demonstrate the sports skill as frequently as possible.
Keep the "fun" in fundamentals. Use a game approach.
Devote a part of each training session to group activity.
If an activity is going well, it is often useful to stop the activity while interest is high.
If a swimmer joins the team after training has begun, skill assessment should be done in shallow water.