First of all a good support is trying to limit the cs of the adc and watch the mini map for a gank. Vision is a must. Take advantage of low hp, give your adc the chance to get the kill. Also you don't want your adc to die. Always play to get the adc out of a bad situation. It is better to lose a turret than to die trying to defend it alone.

Most importantly max out shatter early, you will find a maxed shatter is a game changer, Good luck to all the supports, Remember our role is overlooked, but we can make the difference in games.