I Know You Think In Your Head You're Attacking & Contributing To Fights...
But when you have the lowest, or 2nd lowest damage in the match, you're clearly not. Having a good KDA doesn't win you matches, stop watching and contribute please. Maybe this applies to you personally, and perhaps it doesn't. It's definitely a VERY common problem however that I'm encountering in every single match that I lose, and even some that I've won (Gold players are most definitely the BIGGEST culprits of this bad habit).
Standing in the back of the fight, looking for the right moment to go in while the rest of your team IS DYING is NEVER the right answer unless you have some massive damage AoE that's about the wipe the entire enemy team and it's about to come off cool down. Seriously, move up, start hitting enemies, and be another body for your damage dealers. Every single bit of damage matters, and sometimes having even one extra body take a hit for someone doing most of the damage can mean the difference between a dead carry and one that wins your team the fight.
There's so many frustrating problems I've been seeing, most stemming from players being unwilling to contribute because they think they don't have enough damage or will die. In one of my recent matches, one of the enemies ended up being 1 auto (33 health) from dying, and my teammate didn't want to help me because his spells were on cooldown. All he had to do was hit her 1 single time with an auto attack while I was alive, and we had the kill. Instead he waited until I was dead and she was 1 hit left, then proceeded to end up dying to that enemy even when he had all his spells up.
If your complaint is "well he flashed in and I couldn't reach", why not position better so that you can reach the enemy? When you have a champion on your team such as a Galio, Riven, Kennen, etc. it's completely obvious that at some point they're going to be using their Flash to engage. You can see your teammates Flash cooldowns using Tab, so there's no reason you can't be prepared for their engage.
I've ranted about this in the past, and I'm going to post it here once again.
HELPING YOUR TEAMMATES IS IMPORTANT.
Don't make excuses and don't blame your teammate for dying when you stood around and did nothing to contribute and help them. Sometimes it is the correct move for a champion to go in on an enemy, but it turns into a mistake due to complacence and unwillingness to fight by the rest of that player's team.
Thanks for considering, and good luck.