This is a good intro guide, but there's still a ton of stuff you could have mentioned.
Obviously with looting comes the possibility of good loot, which if the looting location is known by more than one person, there's a good chance multiple people will show up. Be ready for a fight if the loot you are trying to get is valuable items such as weapons and armor. As an example, one of the bloodiest fights for some loot was between Magnanimis and Deldrimor for Benalex's loot, and it took place in an underground store room maybe the size of 15x15 roughly. The total kills of both sides when all was said and done was around 150+.The battle was extended and lasted for over 11 hours. Also be prepared to camp the location for hours in advance if the faction hadn't disbanded yet. Maybe setup a hidden portal nearby or a bed, and use the time before the faction disbands to scope out the entire location, see if you can find a way into where you suspect the loot is to get a head start, or fight off other people that are trying to get the loot.
A lot of people with valuable loot keep their items locked away securely in an alternate faction hidden somewhere. If you notice that someone that is well established on the server is starting to go inactive, maybe do some searching around and see if you can find out if they have an alternate faction, and where it is. Make a link of the location on the dynamic map using the little chain in the bottom left. Then bookmark that URL to bring up that exact location again at a later time.
Just because it looks like you got all the loot, doesn't mean you did. A lot of times there will be secret rooms with the most valuable loot hidden inside. Take traits like Haste2, HealthBoost2, and FallInmune. Then do a bunch of digging around the first looting area you came to. If you're underground, dig straight down to bedrock and see if you drop into another room. If not, go back up and then dig 100 blocks in all the cardinal directions or until you hit the end of their claim. If you don't find anything, just start mining out tunnels at random intervals in between the tunnels you just did, and see if you can find anything. Lastly, if you've found nothing so far, go to the surface (if you aren't already there) and mine straight down from the surface into the first room you hit, and see if there's anything in between the surface and the room. If you've found nothing, then there's a good chance there's nothing more to be found, or the person has another location separate from the one you're at, and you'll need to find that one and do these steps all over again.
When it comes to knowing where someone's loot is, the best way to find out is simply by having that person show you. This is going to sound aweful, but for example, in the case of friends, if you know where their loot is, there's a better chance you can get there first, and either loot it for yourself, then decide whether you want to keep the loot or save it incase your friend comes back. I'm not saying make a dynamic map link of your friends loot stash and then religiously start watching their /seen, but just make a mental note so in case your friend ever goes inactive for reasons beyond their control, such as a broken computer or a long vacation, you can get to the loot and save it for them if their faction disbands.
