How to know who's taller in some ship:
-Says in a quote that the smaller male  does this or that.
-Says in a quote that the taller male  does this and that.
-One of the person's perspective says he/she looks down to the person.
-One of the person's perspective says he/she looks up to the person.
-Addressing someone is cute (usually the taller person says that, sometimes the small person will say it.)
-Says someone is hot or handsome.
-Addresses what the person looks like specifically.
-Blushing...nah, scatch that.
-Someone in the coments answers someone's question.
-The author tells you in the comments. (Or answers someone asking, or they just telling you who's taller/smaller in the beginning of the story.
-Telling who's dom (Dominat, that happens alot)
-Telling who's sub (Submissive)
-Someone flirts with the other (that on I'm not sure of because sometines the other does the same thing)

I think this is accurate...Idk, forgive me If I'm wrong.