How long do you wait between ending your novella, and then revising the manuscript?
I once tried editing my one novella down to the size I originally intended. But then it ended up as 10,000 words instead of the 16,000 words I originally intended. (I was going for a chapter book.) Now I have this 20,675 word honker with the experience I'm not really sure how to replicate.
I did finally figure out how to end my novella, so now no more cliff hanger. But I have another problem, I ended it without series potential. (Well not a problem, I did it on purpose. I don't ever want there to be a sequel.)
Now I'll be outlining my next novella.
You wait until you want to. Then you wait.
I waited about 6 weeks, but that was because life got in the way.
Helps to work on other things while you wait for the story to settle in the back of your head. The trick is to get stuff into the front of your head, I think, and push the completed work into the back, with the quite, cloudy parts of your mind to work away.
I wasn't thinking earlier when I did draft one. The way I've come to figure out subplots sometimes, is remembering that some parts of the story don't make sense with the regular A plot being how it is, and sometimes this can be clarified with a B plot.
This is assuming you already have a 10,000 to 20,000 word novella draft.:p