Best way to solo queue is to find a dominant mid that ganks and semi carries well.
My personal favorites are Gunblade, Hag, Dampeer, Chipper, Pyro, Repulsor.
When I'm boosting I typically just play Gunblade every game because he's perfect for A) raping mid,

killing someone at 6, C) shutting down many popular heroes that can oppose you (monkey king, magebane, hag, night hound), D) carrying well. Plus people aren't smart enough to get armor until at least 1750 it seems lol. Win about 90-95% of games with him solo queueing and boost mmr quickly with mainly 15-20 min concedes.
Just find YOUR hero, or one you're comfortable with for winning mid and ganking. Then go from there. Oh, and buy TPs mid and gank other lanes "sneakily".
This post was edited by Bloodrushdx on Aug 22 2013 11:03pm