As a mastery 7 sona support player, Ive always focused on healing rather than dealing. With all the healing items combined your heals are 50% stronger and grant bonuses. You also have a toolbox of additional heals. I play really defensively and I am always on the move. Your goal is just to keep your ADC alive and dont die yourself.

I am also a mastery 7 blitz support player. Yes, support is my main role. Starting E help leash your jungle better and really catches people off guard. I generally dislike attempting the snipe Q and watch it get flashed, so instead I rush in with E and force the flash before I Q as to make it FAR easier to land. ZZ rot and banner of command help out with mid game money so you can build your late game tank items. Never keep pushing with the wave, just set the ZZ, banner the seige/caster minion and maybe R a huge wave and leave it. You are always needed with your team to fight with them. Blitz doesnt need flash in my opinion, because why does a tank that has a pull need it? To escape? Better you die over the ADC or mid. To better than your Q? THEN WHY THE HELL ARE YOU OUT OF POSITION AND WASTING IT ON THAT?!?!?

Galio is a support generally to be played with a duo partner, your preffered partner is a Kalista player. The lvl6 wombo combo will win the game. Kalista ults galio in and then he ults and free team wipe. Play defensively early and be very liberal with your mana and poking. If the enemy cant farm you get ahead. Once 6 killing should be very easy. Do help your ADC with relic shield farm as well.

Vi support is meant to be played with a well distinguished duo partner with ALOT of practice. Vi is not excessively tanking and will counter all other tank supports. Your goal as a Vi is to shred the enemy of all their armor and let your ADC get true damage on them. Late game you become a scary bruiser of damage. So even if your ADC cant get very fed you can still pile on the damage with your 3 auto attack resets and %hp damage. I like to play Vi with a Corki so the enemy has no way of preventing the damage coming to them.