Taking a quick look, you seem to stomp or get stomped as Master Yi and have a low-ish CS score for the game's length. It might be possible that you are attempting to do too much early-game and falling behind for it; you should prioritize farming and take opportunities to gank when they arise.
Honestly, you seem to have the same issue with Vayne.
Both of these champions scale extremely well into late-game so all you really need to do is get there. Even if you aren't snowballing yourself, you will eventually gain a lead over most opponents as long as you stay relatively even with them simply due to how they scale.
Similarly, your builds are a little weird at times. For example:
- You built Wit's End on Master Yi rather than Maw of Malmortius
- Trinity Force on Vayne
- Double Phantom Dancer on Vayne (she works well with Statikk Shiv or Rapid Fire Cannon if you want a second one)
- You rushed Lord Dominik's Regards third on Vayne against a fairly squishy team (only one of them had any armor and none of them really built a lot of health)
I haven't played in Silver since early last season when I started playing ranked, but I found that the following qualities worked quite well at that MMR.
- Durability.
- CC (for peel, initiation)
- Waveclear/poke
Many players would try to pick low-utility carry champions which would leave the team rather squishy and without any real peel or initiation for said carries. I primarily play CC tanks and durable fighters in the jungle, so I could often fill this gap for my team which would make them far more effective in fights (since they wouldn't instantly die).
Also, I found that players would often group around objectives for long periods of time without really taking it (i.e. Dragons, Baron, towers, etc). Both teams would be standing within vision range of one another and just dancing back and forth until someone was caught out and a fight started. I found that champions with good poke and waveclear were very valuable during these standoffs, since you could easily poke the enemy team down long before the fight started.
When I was climbing through Silver last season, I primarily played champions who could take advantage of and/or cover these weaknesses.
