For most, graduating out of university is the end of the person's education life and possibly the foundational step prior to starting their professional life. People spend a good proportion of their lives learning and obtaining the skills they need to be in the career or lifestyle of their dreams. Hence it is always a precious moment in their lives, and is always worth photographing.
Photographing for graduations to me is a combination of portraiture and event style photography. More-so portraiture for me personally. Its all about capturing the student in their regalia gowns, the companionships that were made during the journey, the family support and capturing the institute where they studied.
My tips for photographing graduating portraits:
1) Make sure that the regalia is tidy and is worn properly
2) Carry safety pins to pin down gowns during windy conditions
3) Advise students with long hair to carry a hairbrush because some pictures you may want the motarboard(hat) and some you may not
4) Include images of just the student and their friends and family in every scene
5) Somehow include the name of the institute of where the student is graduating from, if you can not find a suitable sign, use an iconic landmark instead.
6) Make them happy, because they all worked very hard to finish their education.