Lisa and I just finished the first draft of a story we are writing together.
I’ve now written a few stories in collaboration with other authors. (One of them, “Saving Face”, co-written with Shelly Li, is up at Crossed Genres.) In general, it seems to work best if the story naturally requires more than one voice, and each author can take charge of crafting a separate one. It is a lot of fun to draft together.
Writing doesn’t have to be done alone.