What NASA should have done in order to successfully execute a moon landing hoax. Well, let's just see now...
To start with, no Apollo astronaut should still be alive to this day since at any time they could talk and expose the whole thing.
If I was going to hoax landing on the moon then I certainly would have followed the army's KISS (keep it simple, stupid) method. The more complex the fakery, then the greater the likelihood of not successfully pulling off the fakery stunt since the probability of finding flaws in my fakery methods would exponentially rise as the complexity of my fakery attempt increases.
If I was going to hoax landing on the moon then I certainly wouldn't have used video cameras to record the fake LM landings and takeoffs onto and from the lunar surface. Why? Because obviously at some point in the future, closeup photos of the lunar surface would show that craters seen in the fake videos were not quite in their correct positions since all NASA had to hoax with were the one dimensional image strips from the Lunar Orbiter missions. And I would have made sure that the fake videos, just before LM landing or just after LM takeoff, never showed objects smaller than the limiting resolution of the Lunar Orbiter photographs since objects this small would have to be faked and readily confirmed as faked years later when lunar orbiting satellites showed that such small and faked objects do not exist at their faked locations on the lunar surface.
If I was going to hoax landing on the moon then I certainly wouldn't have allowed the LMs to record a continuous data stream of their gimbal angles during descent and ascent, nor allow the LMs to record the final gimbal angles of the LM orientation and attitude on the lunar surface. Why? Because then every fake EVA photo which has the fake LM visible somewhere in the image frame must have the fake LM properly positioned such that its attitude and orientation is precisely correct to match the gimbal angles, regardless of what fake moon set is used for the fake EVA photographs. Instead I would have made sure that the fake LMs always landed on flat and smooth terrain. Then the fake moon sets would always be level, dramatically simplifying the fakery requirements when switching from one fake moon set to another. Today computers and CAD programs can be used for forensic photographic analysis, and such procedures would show discrepancies in LM orientations between sets of fake EVA photographs taken near the LMs and much further away from the LMs. By the way, this sort of analysis has already been done. No fakery found. Surprised?
If I was going to hoax landing on the moon then I certainly wouldn't have even considered trying to fake the orbital lunar surface panorama camera photographs which were taken by the ITEK 24" focal length panorama cameras located in the CSM sim bays. The most which I would have considered trying to fake would be the photographs taken with the Fairchild metric cameras since the Fairchild cameras had only a 3" focal length lens. And in particular I would have never allowed either camera to take photographs of the fake landing sites before and after the fake LMs had landed.
If I was going to hoax landing on the moon then I certainly would never chosen any fake landing sites which featured large and readily identifiable terrain features such as Hadley Mons. Instead every fake landing site would have been carefully chosen to be flat and featureless much like the Apollo 11 landing site. Why? Because then you run into the issue of having to make sure that the topography of such large terrain features is exactly correct and far more accurately correct compared to the crude laser altimeters of the time period which were flown in the CSM sim bays. And because a flat and relatively featureless landing site is much simpler to fake with fake moon sets. With Hadley Mons for example, if I am not 100% correct in my terrain models, then features along Hadley's ridge line as seen in my faked EVA photographs would either in reality not be quite up to the ridge line, or (far worse) would eventually be proven to have not been visible (over the top and beyond the ridge line) due to perspective from the camera location from which I claimed that my fake EVA photos of Hadley were taken from. My DTMs of the Apollo 15 landing site would, for example, have to be at least 20 times more accurate than what was achieved by creating DTMs from the Apollo 15 24" focal length ITEK panorama camera.
If I was going to hoax landing on the moon then I certainly would never have decided to "fly" either the Fairchild Metric Camera or the ITEK Panorama Camera in my fake CSMs for the reasons above. And all I would have to do, when asked why high resolution cameras weren't flown on my fake Apollo missions, was to correctly reply that cameras with those capabilities are highly classified by the U.S. Air Force. This would be the truth. In fact and to this day I am surprised that the U.S. Air Force allowed these highly secretive cameras to be used by NASA for the Apollo program, cameras which weren't declassified until decades later because their designs were simply amazing in terms of technical achievement and capabilities.
If I was going to hoax landing on the moon then there would have been no lunar rovers since using rovers would require either absolutely huge fake moon sets or a plethora of smaller fake moon sets. Again, why make the hoax more complicated when doing so exponentially increases my risk that my hoax will be exposed as a hoax?
If I was going to hoax landing on the moon then years later (today) I certainly wouldn't have allowed Arizona State University to continuously receive a live data streams from the LRO satellite because I would need time to once again fake all LRO photographs which show the fake landing sites. My only alternatives would be to bribe all of the non-NASA LRO team scientists so that I would have time to alter the LRO photographs of the landing sites, or to set up a reception system so that I would be able to give the received LRO data to the ASU scientists from time to time in large chunks after I have had the time to have my fakery team edit all LRO photos of the landing sites, or instead to simply axe the LRO mission in the first place by claiming that it wasn't in my NASA budget or that other proposed missions had much higher priority.
If I was going to hoax landing on the moon then I certainly wouldn't have had lunar rovers with high gain antennas for transmission and reception, because then I would somehow have to fake transmissions from the lunar surface so that the Soviet radio observatories would also see transmissions coming directly from the lunar surface. Then I would have to fake data transmissions from the deployed ALSEPs by putting some sort of fake transmitter on the lunar surface so that the Soviets could correctly see these fake transmissions as coming from the lunar surface. See:
articles.adsabs.harvard.edu/full/1978SvAL....4..302NIf I was going to hoax landing on the moon then I certainly wouldn't have allowed fake photographs of the Earth to be made which show fake weather patterns across the globe at any specific date and time. And I would have made sure that such fake photographs were always taken by a fixed camera rather than being taken by a hand held camera from within my fake CMs. Why? Because this would eliminate my need to simulate camera depth of field, thus eliminating my need to make sure that the out-of-focus blur of the CM window frames matches what should be seen when the camera's lens is focused at infinity (to photograph the Earth) and eliminating my need to superimpose a sharp photo of my fake Earth atop of my fake photos taken from inside my fake CM. Computers capable of running digital image processing programs didn't exist during the time of Apollo. Thus overlaid photos of my fake Earth, when forensically examined today, would readily and easily be revealed as a fake composition of my fake Earth and my faked photos from my fake CM interior and window frame.
If I was going to hoax landing on the moon then I would have made darned sure that there was a nice lunar surface blast crater directly underneath every LM descent stage engine since I would have assumed that this would naturally occur and since I would not have known that the lunar regolith roughly a foot down is very tightly packed due to a few billion years of continuous micrometeorite bombardment.
If I was going to hoax landing on the moon then I certainly wouldn't have allowed any fake EVA photographs which show the Sun in the frame since my spotlight for the fake moon set must match the apparent size of the real Sun and since my spotlight would fog the film, allowing the film to have a very high likelihood of faintly recording the support for my spotlight even if my spotlight support was draped in black cloths.
If I was going to hoax landing on the moon then all of the fake lunar samples would have been very similar since I wouldn't have known that the lunar geology varies considerably more than was predicted across the lunar surface.
If I was going to hoax landing on the moon then I certainly would have run out of money for bribing the thousands of people I would need to help me fake the moon landings, including the money I would need to continuously surveil them for decades in order to make sure that they don't start talking. I figure that I would also have to eventually eliminate at least 10% of them and their families using a variety of mysterious "accidents" since some people just can't keep their mouths shut. There would be those who would come back and demand more money. They would have to be eliminated since they would always come back, demanding more money and threatening to talk if they didn't get it. There would be those who would eventually have a conniption of ethics and decide that they can't keep living with keeping such a big secret. They of course would have to be eliminated, and their families too since they likely would have already told their spouses about the "big secret." There would be those who would eventually develop substance abuse problems. They would have to be eliminated since minds under the influence of drugs are unpredictable. I certainly can't have anyone spilling the beans since I know that I would go to jail for the rest of my life for fraud!
If I was going to hoax landing on the moon, then I and others at the "top" of the hoax program would eventually have been randomly eliminated over a period of several years after Apollo, assuring that the "top masterminds" behind the hoax could never reveal their secrets. All "accidents" would have appeared to be completely natural and most unfortunate. In other words and in reality, such a large conspiracy is virtually impossible to pull off because, in reality, there would never be 100% control of all of the involved conspirators. If one starts knocking off conspirators who threaten to talk, then the rest of the conspirators would all start talking at the same time in order to save their own hides, fully exposing the conspiracy.
To succinctly answer your question about what NASA "should have done" in a real moon hoax? Nothing, since trying to create such an elaborate hoax would be impossible for the reasons described above. And the reasons I list are only the tip of the iceberg of why the notion of such a hoax would be impossible to successfully execute.
So this is the long and the short of it. The fact that overwhelming evidence exists, evidence which for a variety of reasons wouldn't exist if a hoax were actually committed, inherently proves that the Apollo moon landings were real.