Ranked Matching

I would really like for someone to explain to me how ranked matches are created as far as who your teammates are and who the opponents are going to be.

I know the saying is about your Elo or MMR, but I feel a majority of my games seem to be unfairly made. I either get someone that was way to high of an Elo against me and their skill is that much higher then that of my own or I do really well in my lane, but every other lane is 0/3 by the 5 minute mark.

I just need to know, is there a secret I'm missing out on?