I'm with you Mr. Stormchaser!
I usually floated around +20-30 wins in Dom, but I've been reverse carried to the -10 area. Is it my fault? Of course! I should have been picking Yorick and rolling bot instead of experimenting with Hybrid Kennen and Twitch! snrk
It doesn't matter how many high level tactics you know and can execute, because those usually require teamwork. You can't rely on your team because they aren't at your level. What to do?!?!??
This is what I've figured out from my short time in ranked SR during Season 1. Play a champion that allows you to control the map. In SR, I found HUGE success from the 800-1250ish range as a jungler. I was free from laning to gank, ward, counter-jangle, add extra pressure to different lanes, ect ect. In Dominion, there's a jungle, but you don't use it for farming gold+levels, you use it for shortcuts and ganking ect ect. This is where my success has come in. Using AP Shaco(lulz) or AP Teemo(lulz again), I prowl around the jungle, primarily on the enemy side, as recon and disruption. I use the traps to both give vision and cut off key points, and sometimes I hang out near those traps in order to gank when I think somebody will come out isolated.
Personally, I'm finding Teemo to be a bigger threat to the enemy team than Shaco, because of Teemo's trap's damage can't be avoided once an enemy hits it...with Shaco, after the fear is over they can walk out of it or destroy it.
I'm not sure where you're sitting, but around -10 W/L, people don't frequently move as a team, and they usually pick a champ that can be exploded within a few seconds of being DFG'd. Play to your strengths and the general weakness of your current matchmaking. My strength, being slippery dippery and picking off scrubs, the weakness of my elo, prideful soloists who all think they are the carry.