When it comes time to teach a "big" dive or learn HOW to teach a "big" dive -- both the coach and the diver need to IMMERSE themselves in the dive.
Both diver and coach should watch video of the new dive; the coach should talk to other coaches who have divers doing the dive or have had a diver do the dive. The diver should talk to other divers who are doing the dive. Ask them what steps they did to prepare for the first attempt. What type of dryland skill work was done? Ask them to describe any pitfalls or problems they encountered when teaching or learning the new dive. Ask if there are any drills or skills that should be practiced over and over to help the diver prepare for the dive. Does this new dive require the coach to make a "call" that they have never made? Should you wait until you are able to do the dive in an over-the-water spotting harness or have access to a "Bubbler Machine"? The list goes on and on. Immersing yourself in a dive is not easy -- but it is well worth your time.
Coaches should be willing to help out other coaches; divers should be willing to help out other divers. Besides just being good sportsmanship -- it can only help to improve the sport.