Outlining a novel. Put any two novelists together, bring up that subject and you're likely to start an argument.
Personally, I'm firmly in the non-outlining camp. I tried outlining which led to a horrible, stinking novel that got firmly trunked. It just didn't work for me which is what I judge techniques by. It can work for everyone else in the world, but if it doesn't work for me, I don't do it.
It's no secret, since he said so in his marvelous On Writing, that Stephen King doesn't outline. There are plenty of others in our side of the divide so don't feel like you have to if you don't. On the other hand, if you've never tired outlining, you might want to try it. I think we can't know what works for us or what doesn't until we try.
I'll be happy to admit there are plenty of good writers who do. David Farland in his excellent email blog "Kick in the Pants" talks frequently about outlining and how to do it. (I stick my fingers in my ears and say, "Neener, neener. . . I can't hear you.")
The other day Dave shared a wonderful article that I want to link because it's a technique that is "outline-ish" without quite being outlining that I'm going to try on some short stories. Maybe this will work for me when outlining doesn't.
They refer to it as "sketching" kind of the way an artist might do a preliminary sketch. It's definitely an article worth reading.