Half the fun and challenge of teaching is constantly adapting your delivery to match the needs of your students. Great teachers are constantly learning more about their subject matter. Teaching experience exposes you to lots of different individuals, all shapes, sizes, and challenges. Try to pick assistant/s that are quite different from yourself. If you have difficulty reaching a student, they will probably succeed. Watch and learn their technique to see if you can improve yours. Instructors always need to pay close attention to their students - all of them.
Thinkers can be fun and quite challenging students. They often look for minutia of information and wait until they feel they know something cold. I provide extensive web-based training material that really appeals to these types of students. Expect them to come quite prepared and ask really interesting questions. Sometimes they can go overboard though - way beyond the level for the class. You may need to take their question offline and get back to them during a break. Another trap some instructors fall into with these students is guessing or making up an answer. If you don't know, say so. Jot the question down, research and get back to them. Think of it as a learning opportunity. Rolling can be a difficult maneuver to teach these individuals since they might over think the process.
Doers are chaffing at the bit to give it a whirl. You know the types, they don't read instruction manuals and jump right into assembly. Sometimes it works, sometimes it doesn't. They then try different variations until they get it right. Pay close attention to form and provide limited guidance to help prevent them from developing bad habits. A great example are paddlers that muscle the roll. Eventually they will injure their shoulder. Help them set up, reach out a bit, and rely much more on a solid hip snap and torso rotation.
Many individuals are visually oriented - show me. They can watch a demonstration a few times, perhaps with some type of narrative to go along and then try the new skill on their own. Many DIY DVDs support these types of individuals. This is where the instructors form and attention to detail are really crucial. Emphasize key components like leaning your boat for peel outs or torso rotation when demonstrating the forward stroke. Great athletes can play back what they wish to accomplish in their mind. Think of a long complex rapid, you scout and make mental notes of key land marks and moves. You get back in your boat, play the sequence in your mind, and then run the rapid as planned.
Some people have natural ability. They are amazing at picking up new sports. They don't need a great deal of talk, just a bit of guidance. Bicyclists understand leaning into turns which is very similar to boating. Skiing is perhaps a better example. Skiers dig their edges and stay upright. Kayakers lean their boat in a similar manner and keep their torso upright.
Most people are various combinations of the above styles. Mix up your teaching styles. This makes the class more interesting and will help ensure you don't lose anyone.
Kolb Learning Styles
The basis for the above types of learning styles from David Kolb's experiential learning theory (ELT). A great article on this subject is: Kolb Learning Styles.