Well said. I'm a 13-1400 player myself though and teamwork definitely exists at this level of game play. You can no longer treat it as a solo game...at worst I get a bad player on a team...very rarely more than just 1.
Aside from that, this thread is full of good advice on how to escape "elo hell"
The way I like to put it is: "High level tactics to no work in lower Elo" This is all encompassing even when you compare the 1700s to the 1400s. There are certain timings and tricks that a 1400 elo player won't know, so as a 1700 player, you cannot rely on certain strategies that depend on the 1400 player executing it.