Lets face it, we all want our clients to recommend us to others in the future. Good interpersonal skills are essential for teachers. Most of our clientel have come to us because they want to learn something new and have fun while doing so. Drill sergeants might work in boot camp but not in our field. Don't forget that many of your students are new to these skills and may lack your background. Differences in techniques are expected, some may work well - others not so. How you communicate your tips goes a long ways in their acceptance.
Group management/leadership skills can be challenging. You will encounter the occasional student that wants all of your attention, don't fall for that trap. Some students will need extra attention to succeed, there are many ways to manage this.
Choosing an appropriate class venue is a critical success factor. Noisy and crowded rapids are a bad idea. First off, you can easily lose track of your students and that can be a major safety issue. High noise and lots of distractions may make it difficult for your students to pay attention to you. Choosing easier rapids to practice tough moves is generally a great way to go. Your students will feel far more comfortable trying new skills if they are not fearful for their safety.