I try to make sure the plot is fairly well structured in advance, although I then give myself the wriggle room to go 'off-piste' as the story develops.
In terms of research, there's always little things, like 'what does poison gas smell like?', or how do you buckle up a saddle, etc etc, but I don't tend to lock myself away for 6 months in the British Library like historical authors must do. Well, at least the good ones (aka Hilary Mantel), Wolf Hall and all that.
Stephen
