I agree with DG, making an effort to know the students goes a long way in making them feel comfortable with you. If at all possible, I'll attend at least one of their academic classes. This probably helps me more than them because it gives me an idea of how well they understand everything. And gives me a heads up as to who will more likely need extra help.
Managing everyone out of the water is easy if you keep them occupied. Talk to them. Some, if not most, students hesitate to ask questions, so you initiate the question/answers first. Make sure everyone understands the hand signals you will be using. Nothing confuses them more u/w than for them not to understand what you want. I use the hand signals on land as well as in the water. For instance, anytime I need to know how much air they have, I'll use the hand signal for checking your gauge, etc. When they get in the water, the practice pays off with little confusion.
Lighten up! If the whole thing isn't fun, no one is gonna have a good time. You can be funny, entertaining and putting the student at ease while at the same time watching everything they do. Then they will feel more comfortable mentioning those things they are wondering about. I make sure I let them know how good they are doing. Find anything they've have done well and tell them so. In pool sessions, everytime a student successfully completes a skill, I clap like a zoo seal! Hey...it gets the point across.
While students are on the platform waiting their 'turn' for skills, after checking OK's, air, cold, reminding them to watch the Instrucotr, etc. the main thing is to watch them for signs. After being with them in the classroom, in the pool and listening to them talk, you'll have a very good idea on which ones need the most attention. Just a touch on the shoulder will do wonders for those that are getting freaky. The fidgety ones are usually the bored ones. If all is going well, I'll play rock/paper/scissors with the ones at the end of the line. Or get out the Magna-Doodle and let them play tic-tac-toe. Just keep one buddy from sucking air from the others octo! Of course you're keeping an eye on the Instructor for signs from him as well as checking the rest of the students.
It's the simple things that will make a big difference. Always be helpful with a smile on your face. Tables! Know them inside and out and be there to explain it again. Some Instructors gloss over the logbook. 'Course ya'll know that's a 'thing' for me so I'll sit down and show them how to fill theirs out. I ask every student to sign my logbook at some point during their checkouts. I keep small gold stars and stamps handy for their logbooks. You'd be surprised how many men enjoy that gold star!
I always have a graduation 'ceremony'. Even though PADI makes certificates, I make my own that goes something like this...
Let it be known all ye mermaids, bucaneers
and creatures of the low viz swamp, that
John/Jane Student
having endured wetsuits that smell, fireants from hell,
wrinkly toes, a sunburned nose,
dry matty hair and damp underwear,
successfully became a
SCUBA DIVER
while at Blue Lagoon
Huntsville, Texas
Always remember that they see and hear EVERYTHING you do and say!