I watched a great live interview with my favourite HF writer Bernard Cornwell, last night.
He gave an interesting tip for writing HF. He has a big story and a little story, and he flips them. So in Sharpe the big story is the Napoleonic Wars and the small story is Sharpe's. In the Last Kingdom the big story is the making of England and the small story is Uhtred's. He flips the big story into the background to act as his setting, and brings the small stories to life.
I was also delighted that he's a complete panster. His technique is to put his hero in a tricky situation and then write to find out how they get out of it. From that a story then develops.
It was run by Fane, and they have a lot of interviews coming up if anybody wants to check them out.