I hope you don't think I'm a master at these games or anything

Shorthanded / Heads up games like we've been playing so far are all about aggression. The biggest difference between how the two of us have played is I have shown strength whenever you give me reason to, and you haven't.
I have no doubt in a larger game you would fare much better than recent results may indicate, as "tight is right" will carry you a long way. However, eventually you need to open up your range and show your opponent that it won't be cheap to play.