Unless you are a Nielsen house, your TV watching habits won't influence the ratings. You are better off buying the products advertised during the program and emailing the companies to let them know you are buying their products due to their advertisements during Dollhouse.
That said, the show had a pretty weak start but has been getting better each episode. Where it really lacks so far is the trademark Whedon snarky humor that makes the characters lovable so you actually care what happens to them. Without that element this show is just a remake of the 90's series The Pretender.