I always hit the history books before I commence a build and for the Spitfire it meant getting a book written by the very man whose plane I’m building! Not every famous pilot writes a book about his experiences but when they do, I read them.
Full Circle by Johnson is a great survey of his flying career and the history of fighter planes in general. Good stuff from someone who lived modern history. Other books of interest to me always include big pictures and detailed photos of actual warbirds. The In Action books are always worth cruising the interwebs to find.
The latest must have books in my humble opinion are the VS series which often pit classic fighters against each other for entertaining comparisons. This is how my aviation library grows in relation to my model collection. Eventually I’ll have no room for either.
I also spend countless hours digging online to find images of the plane I’m about to build. Reference pictures are invaluable whether snagged from the web or obtained in person from a museum visit. Unfortunately there are no Spits in Idaho, at least that I’m aware of.
However you do your research, just do it. It makes the hobby enjoyable in so many ways. I also watch movies that feature the planes I’m building. The Battle Of Britain, Bader’s story and even Dunkirk are all valuable resources. Hurry up and come out – Dunkirk DVD!