I think the #1 priority is have the tools available to the diver to make those weight distributions. That was always the issue at the few dive shops I rented from before getting my own gear.
1. Have a wide variety of incremental weights, especially in the #1-2 range.
2. Have the trim pouches installed on cam bands.
3. Have 2 cam bands BCDs.
Now that the tools are available. It is about providing that instruction, from both your instructors during courses and your DMs on the daily dive basis. Especially to those renting dive gear, some divers just won't care, but others will be interested in getting better. Part of that is also about helping them get properly adjusted in the rental gear. Too often gear is just handed out with an adjust it yourself mindset. But, getting the shoulder straps the right length, waistband/cummerbund adjusted can all make a big difference to a diver before even adding weights into the mix.