For those that are doing advanced pull up exercises, you have a lot of options to try. You could do mega sets, pyramids, supersets or do as many as you can in a set period of time. These types of workouts are probably not good for someone new to pull ups, or new to working out for that matter due to the potential for overdoing it.
Try doing as many pull ups as you can, say in one minute. You could use this as a barometer of your progress. Maybe every month you could do this to see what strength improvements you have made.
I call one way of working out mega sets because you would do many sets, you might take a long enough rest after a set to fully recover before doing the next set. You might do a total of maybe 8 to 10 sets. You would not do this type of workout very often, but it’s a good way to break past a pull up plateau.
Try doing supersets of pull ups together with another exercise like push ups or maybe bench press. Do one set of push ups and immediately go to the pull up bar for set, rest for a few minutes and do it again. How many sets you do is up to you.
Doing pyramids is a good way to do a lot of pull ups at one time. You just do one and rest, two and rest on up for as many as you can do till you can not complete a set then count back down. This can be a good way force yourself past a sticking point.