Plotting. When you read a scene in which someone is describing something that happened somewhere else, what you're reading is twice the work of your regular, it's-happening-right-now scene. You have to plot out the events that happened elsewhere, you have to plot out the here-and-now. Both sets of events must happen in your head as if they'd really happened. The characters must live.
It's a pain in the ass, but it saves leading into the other scene and following out of it. Also, it helps conceal information that should not yet be revealed. In addition, the storyteller can lie much more easily than the writer can lay the scene flat-out and still deceive the reader.
One of the things that's making plotting on this damn story bearable is the fact that I have characters who lie.