Knots quite frankly frighten many students (and some potential instructors as well).  This is why we concentrate on a few basic knots, especially the figure eight family.  As a potential instructor, I suggest practice tying these knots and become quite familiar with their various uses.  Here are a few articles I have put together to assist you:

• Figure eight family
• Additional important knots
• Many other knots available; these form the foundation of river rescue