Taking on a huge project like a novel is sort of like trimming a meadow with a nail clippers. It certainly can be done, but, hell, where do you start?
It's a funny thing, writing a novel. Because you are creating an alternate reality, it requires you to act like a crazy person while you put it together.
I do profiles of every character. I think about what they wear, what they eat, where they went to school, what their first romances were like. I choose residences for them around the city, and later, when I walk past, I look in their windows and think about what they are up to.
Let us be frank: these are the actions of a crazy person. But if you don't believe in the people you create, how can you expect anyone else to?
I do a lot of site research, walking all over Manhattan taking snapshots of where my characters walk, work, and socialize.
Naming the characters is fun; many of them go through several names before I decide on one I like. This is a real benefit to my line of work. The average woman gets to name one? three? ten? people in a lifetime. An author gets to name dozens and dozens.
The plot, I work out through an outline, which goes through endless revisions. I like to know where I'm going, or at least where I intend to go, even if I don't ultimately end up there.