You look more average than bad based on the information that's visible to me. But as somebody who constantly ends up as support in the same divisions you're in, I can tell you the mistakes I see my adcs making a lot of and if any of them apply to you, you can work on it.
First, as a support, I will ward whenever I can, but there's a limit to how much I can ward before I run out. At that point, you' need to be ridiculously careful and not overextend no matter how well you're doing. The best thing to do in this case is to either tower hug or push past river and back with the support to get more wards. I can't tell you how many times I'll actually tell the adc I ran out of wards and they want to tower dive or something stupid.
Second, once a tower goes down (and it doesn't matter if it's yours or theirs), the laning phase is over. At this point, you're generally going to want to just push bottom lane till it goes the other way and then go mid. However, if it was your own tower that went down first, you have bot lane push, and can see all the other enemies on the map are out of reach; you can go ahead and take the enemy bot tower. But too many times do I see adcs continue to focus bot instead of mid after the laning phase and leave the team shorthanded by making themselves easy targets.
Third (and this applies to everybody, not just adcs), when there is a lane pushed towards you right next to you, DO NOT JUNGLE! I honestly have no clue why the hell people are so insistent on jungling during the team fight phase, but it outrages me to no extent. The only valid reason to jungle during the teamfight phase is to either get an objective like a buff, or because every lane is pushed the other direction and everybody is too split up to go further safely. There are good times to jungle, but 9 times out of 10, you should just be grouping.
