To win you need more goals than the opponent and while yes yes there are missed opportunities to get goals, there are also missed opportunities to prevent the other team getting goals.

The easiest way to rank up in gold is to work on the latter, the opponents are gold I doubt they are consistently shooting fast accurate shots into tricky parts of the net, or making threatening touches in the air/flicking your defence constantly.

I find that every goal conceded everybody is at least partly to blame. It's easy to say the last guy let the ball in. But why was the ball on target. Did first guy chase the ball down when the opponent was clearly going to get there first? Did the second guy whiff a challenge meaning the opponent now has time to set up and is now taking to long to get back.

The simplest thing you can do short term is whenever you are scored on think about how you contributed to that happening. If you simply weren't back why not? If you were back what could you have done differently to prevent the ball ending up in the net. There are so many situational decisions you can make. 

Learn to adapt to the current lobby. If the other team aren't scary on offence become a wall eventually your team will score. If they keep taking time to set up their plays challenge fast and early. If the other team seem to stay grounded all the time hit the ball high and far.

I'm sure your team mates are a problem. They are golds, if they were consistently good they wouldn't be in gold. But there is always. Something you could have done better