So I've played support like twice in the past week, both times I've gotten S's. (I am also sure I received S scores on these two games because I got champion tokens)
The most recent game was with Morgana, where I went 4/2/21, contributed 58% to the total damage dealt on my team, placed 30 wards, and destroyed 5 wards. My total gold was 15k.
The second game from about a week ago was with Janna, where I went 1/7/19, contributed 39% to the total damage, placed 31 wards, and destroyed 11 wards. My total gold was 14k.
I also won both of these games.
With Morgana I got an S.
With Janna I got an S+.
Let's check your stats now...
http://euw.op.gg/summoner/userName=VioletWolf
I can't say I see a support game of yours where you're 1/2/42...but...
Zyra, 2/8/6, 38% dmg contribution, 18 wards placed, 1 ward destroyed, 9k gold. (loss)
Lux, 1/3/1, 20% dmg contribution, 20 wards placed, 6 wards destroyed, 6k gold. (loss)
Sona, 1/6/6, 41% dmg contribution, 11 wards placed, 1 ward destroyed, 7k gold. (loss)
Nami, 3/6/23, 49% dmg contribution, 40 wards placed, 0 wards destroyed, 14k gold. (loss)
Thresh, 1/1/11, 33# dmg contribution, 20 wards placed, 2 wards destroyed, 7k gold. (win)
However, stats aside, I've noticed that you have a trend of not buying items?
Your games are, on average, 30 minutes long, yet you only have two items? Usually
and
. And then a
that you should have probably placed instead of hoarding it in your items. And you rush upgraded boots?
I mean, to be fair, let's look at my stats when I lose a game:
Sona, 3/6/17, 83% dmg contribution, 22 wards placed, 4 wards destroyed, 10k gold total. (loss)
However, with my 10k gold, my build was 





Granted, I still got an A that game. But let's just look at those key differences. When I'm losing and I'm behind, I'm still building items with the gold I have. When you're losing and behind, it looks like they first item you're saving up to buy is a
.
So, perhaps you should try optimizing your gold to buy items that can help you support more effectively.
Maybe instead of rushing the upgraded sightstone or boots, you should rush your first support item. For mage supports, like Zyra or Lux, it might be better for you to rush
instead of building
because the active is great for initiating or chasing--which would help you as a support. For Sona or Nami, or anyone with a heal or substantial shield, I personally rush
because the passive helps my adc in fights.
Just my two cents.