I think it's great that you are getting into coaching golf. I played all four years in high school and had an amazing coach so I'll try and give you a student's view.
In regards to the game, don't try and change a player's swing too dramatically. Give them easy fixes such as keeping their head down or using a line to aim their puts. My coach called them "band-aid fixes", things that are easy to do and will have a profound effect on a rookie player. Next, you want to go over rules. No need to teach them the entire rulebook, just everything they will have to deal with in a typical round of golf. This goes hand in hand with integrity/sportsmanship. Make sure you are encouraging honesty and respect toward other players. Lastly, and most importantly, point out how difficult the game is and make the kids understand that they will hit bad shots, have bad rounds, and may be expecting too much of themselves. Let them know they are still young and experience plays a huge part in golf. It's ok to make mistakes.
From a coaching standpoint, take an interest in the kids and think of them as your own. For example, instead of holding a meeting, my coach would drop by my house and drop off the required paperwork and chat for a bit. I'd get invited out to a couple rounds with him and my tennis coach...ect. Make practice a reasonable length and encorperate different competitive drills. To get the players to aim at a target when on a range instead of just pounding balls, hold a "closest to the pin". On the greens, start with a short game lesson of the day, have the players practice it, and hold a quick short game match play tournament where the winner gets a gatorade or soda from the clubhouse.
Finally, there's one overlooked inevitability of being a coach. Bureaucracy. You'll have to make sure the students all have their paperwork in (I know in Maryland we needed a parent permission form and a physical), keep track of their grades so they can be elligable, and deal with other coaches and your athletic director. You might have to keep a tight budget because all the money always seems to go into football and never the niche sports, so just be aware of that.
Sorry about the wall of text, but if you go in there with the best intentions (and by your first post it certainly seems like you are) you will be a great coach and maybe even an inspiration for your students. Good luck!