One way to do it is to choose a flower that is the same colour as that of the school itself. If the colours are white and red, go for red roses and white lilies. Mix and match both of them and arrange them in an impressive fashion in a bouquet. In case you are not sure about the school colours, choose the colours of the graduation gown as an alternative. Another way to do it is to prepare a bouquet that will stand out in the graduation photograph. Gifting something that they can use as home decor, later on, is also a good idea for a graduation ceremony.