My approach for residents/fellows/recent grads is usually pretty much the same. If I see them in person (not typical situation), I will discuss in person. Usually, I send the information via e-mail.
I start off by letting them know 1) this is probably not information that was covered in their many years of education (or certainly not in depth), 2) more complete documentation/coding can result in more comprehensive patient care by the entire team and is essential for reimbursement & 3) I am always available to them as a resource. I let them know part of my job & responsibility is to make sure our practice/facility gets PROPER payment for all of the amazing care they are providing, but I need their assistance to do so.
Then get into the nitty gritty of exactly the best way to code the scenario. Type up a little table, showing them exactly how many "abnormal PAP" codes there are and how each one means something slightly different.
If the first e-mail gets ignored & the same issues are occurring, I send a follow up e-mail asking if they have any questions, or if I was unclear, again re-enforcing that I am a resource for them. If the 2nd e-mail gets ignored and the same exact issues are occurring, I send another e-mail asking if they would like to meet to discuss, as their documentation and/or coding is impacting the payment to the practice/facility. If it still doesn't get resolved, I then loop in the program director, or attending physicians. In my several years of dealing with residents/fellows/recent grads, I have only had 1 that just did not want to hear about documentation & coding. Most of them are appreciative of the help & knowledge I can offer.
I think your exact approach should vary depending on your personality & the personality of those you are trying to guide. I really try to keep it educational, informative and collaborative unless they intentionally do not want to cooperate. Remember the goal is better documentation & coding, so whatever I need to do to accomplish that long term, I will try.
Good luck!