Keep in mind. If you are short-stacked and your opponent is appropriately aggressive, you are going to lose greater than 50% of the time. No amount of skill will beat aggression in heads up play, if you're outchipped and the blinds are high. It's good to fine-tune your game and make sure you're playing like 'rilla says, but that still is not going to make it so you win all the time or even most of the time when you're short-stacked.