The agency does not necessarily make a good instructor. There are excellent instructors & not- so- good instructors in every agency. The skills & knowledge can be learned but these are a few things that do help to make a good instructor-
Mentorship- Get with a known good/ excellent instructor. Have them take you under their wings, if they will. Watch them, watch what they do & learn why they do it & why it works.
Experience- Have the biggest & best "tool box" of experience you can have for your students. Don’t just go for the bare minimums to get through. Would you want your family/ loved ones taught by someone who just had those bare minimums met? Be the instructor you would want your loved ones to learn under. Have experience in deep diving (rec limits), night diving, navigation, cold water, murky/ low vis water, rough seas, currents,... anything you can come up with that can make diving challenging. Know how to dive those, so you can pass on those experiences. I always look at my Open Water classes as though I am bring along the next generation of (safe & competent) divers & I take that responsibility very seriously.
Empathy- Many of your students will come with concerns & sometimes even fears about their course & their abilities. Don’t just dismiss their concerns & questions. Listen to them & tell them, step by step, what you are going to do for them to alleviate their concerns. Encourage them as they learn & master the skills.
Humbleness- Be humble, don’t boast or thump the chest. Even though you may be better than your students, at that time, quietly show your quality, don’t shout it out. VERY IMPORTANT- Always remember where you came from. You did not start at the top of the mountain, you are not the biggest gift to diving. Just be humble & honest about your knowledge & skills. People respect & appreciate that more than trying to be loud about it.
Always keep learning, even as you instruct. Further your knowledge into other realms of diving,.. many of these other types of diving will compliment or even improve your skills & experience as an instructor. I have sworn that the day I quit learning about diving, will be the day I will hang up my fins for the last time.
Last thing I can come up with is be real to your students. Leave your personal issues at the door, when you come into a class. Be enthusiastic! Be passionate!, be alive!,.... You will find that it is contagious & will ignite the flame of diving within your students. I have been lucky to have a large % of my students that go on to be very active divers & some are now even becoming professionals themselves.