Brilliant author/editor Teresa Nielsen Hayden has posted her "Evil Overlord" formula for devising a plot for your flagging science fiction story. It's terrific.
* A plot doesn't have to be new. It just has to be new to the reader.
* In fact, it doesn't even have to be new to the reader. It just has to get past him. (It helps if the story's moving fast and there's lots of other interesting stuff going on.)
* A plot device that's been used a thousand times may be a cliche, but it's also a trick that works. That's why it keeps getting used.
* Several half-baked ideas can often be combined into one fully-cooked one.
* If you have one plot presented three ways, you have three plots. If you have three plots presented one way, you have one plot. (I stole this principle from Jim Macdonald's lecture on how to really generate plots, which is much better than my lecture on stupid plot tricks.)
* Steal from the best.
(via Making Light)