Ranked Chaos

I'm very confused when I play ranked. I have played a ton of games in which my teams start off 0/10 in the first 10 minutes (while I am sitting at 0/0/0... you know the "team members die when you are 10 feet from being able to gank") or I am 4/0/4 but my team is a combined 3/19.

I ward and play smart, but my team is playing so bad that I eventually go from 4/0/1 to finish off 6/6/7 or something like that because my adc had decided to be a front line Ashe (when we are behing of course) so she just gets 1 shot. Or my supports, on average, only put out 15 wards per game. Yes, I still have the occasional bad game, just like anyone else does, but I'm stuck in silver 4/5 right now and I just cannot seem to get out of it.

I've gotten to Silver 3 promos this season perhaps 6 times only to lose out due to quitters or heavy feeders or that one bad game. I even dropped from Silver 3 promos down to Silver 5.

I have witnessed a lot of poor decisions about where to be, where and when to ward, when to back, when to engage, when not to engage. Knowing how team comps can easily win fights, unless we're amazing, but it is silver 4/5 people so that rarely happens. Knowing when to stick around and keep split pushing to draw teams into chasing you so your team pushes other lanes.

I just cannot seem to crack it. In fact, I've just recently went from about 7 games over .500 to 3 games under .500. When I lane I get over 250 cs. When I jungle I ward in the best locations, counter gank, counter jungle,

Normally, I am even or ahead on CS a lot, but rarely ever get ganks. I am waiting for the game in which my team wants to feed me, but that never seems to happen.

Pushing mid turrent when top and bot minions are pushing towards our base, while also not having a great 5v5 comp against their team of heavy cc is what my teams like to do all the time.

Also, people like to split push without others also pushing different lanes or without wards = dead split pusher.

Not knowing how to rotate lanes, or when sieging is more important than engaging so that your minions may push up on a turret, take a turret, or pull someone from their team away so a 5v5 turns into a 5v4 or better odds.

Also, not many people know that when you take a turret (if you are bot lane) you then swap or just heavy push and take mid lane as 3. (Usually mid or bot get butt hurt when I ask to swap lanes)

Any advice?