Cut like crazy. Less is more. I've often read manuscripts - including my own - where I've got to the beginning of, say, chapter two and have thought: “This is where the novel should actually start.” A huge amount of information about character and backstory can be conveyed through small detail. The emotional attachment you feel to a scene or a chapter will fade as you move on to other stories. Be business-like about it.
Respect your characters, even the minor ones. In art, as in life, everyone is the hero of their own particular story; it is worth thinking about what your minor characters' stories are, even though they may intersect only slightly with your protagonist's.
I've just finished a series of Olivia Manning novels. She's best known for two trilogies: Balkan Trilogy and Levant Trilogy. The six novels are continuous and contain the same set of characters. They are based on Manning's experiences in Eastern Europe and Egypt during the Second World War. Each novel is a wonderful picture of the peculiar British expatriate culture and what was happening during the war. She's one of those brilliant women who write very well about domestic relationships. All the books are slim, and it's easy to gallop through them.
