Its a lot harder for most folks because you have to know starting
hands for heads up, lol.
That changes from full ring or 6 max so you brush up on it then you have to play the player.
Are they tight?
Why are they tight?
Do they actually know the starting hands then you might be in trouble.
Most folks that play tight HU aren't timid but they actually have a clue what they're doing and they're waiting for novices to make mistakes.
Or are they aggressive crazy maniacs that think they can play any hands?
I mean there are books on how to play HU and Moshman has one on heads up, Tipton has a series of books on HU play but once you know and understand the game you're playing then heads up is the best format for it.
IMO, HU and HU sngs are a true indicator of a player's game knowledge for whatever level you're playing.