What are key heads up lessons?

[aujoz]

I've just started playing 10+1s, after finally "getting it" (in terms of playing well) at the crazy easy 5+1s. At the 5+1s, I won about 86% of heads up, while at 10+1s, I win only 46% or there abouts.

While it's not from a massive sample, this tells me that there's significant room for improvement playing heads up - for a newbie like myself, what basics are worth learning?