well id say that the 3 essential equipment for shooting waterfalls are tripod, circular polarizer and ND filter wich reduces the light by 2-4 stops atleast. and what comes to composition try to pay attention to the foreground, mid ground and high ground try to balance the photo right so that the viewers eye can flow through the photo generally you dont just want them wandering around the picture try to make them look it in a certain way. i dont know if this was any help but i tried :-D