Originally posted here.
If you are more of a visual thinker, have you maybe tried drawing a story map? Not all plots move around in space as well as time, but even if your characters aren't literally moving from place to place they still have to progress through some kind of process, right? Something has to happen to them that changes them fundamentally.
Try taking a big sheet of blank paper and about three or four different colors of pen. Use thick black lines to mark the parts of the story that are both already written and crucial to the plot. Then use other colors as necessary to fill in bits that you wrote, or things that you know need to happen but haven't written them. Use arrows to connect them together, like a flow chart. Then take a pencil and start pencilling in possible solutions for the blank spots.
Example: in blocks 1 & 2 the hero and heroine meet, and initially dislike each other. Block 4 is the hypothetical point where they're supposed to realize they're in love. In the blank space where block 3 would be, you pencil in some possible scenarios that would help them transition from disliking each other to grudging respect -- like the hero helping the heroine with a very embarrassing personal problem, without expecting compensation.
If you're not a very visual thinker... Well, what are you good at? What do you like to do? Try to adapt a problem-solving style that you're already familiar with (jigsaw puzzles, knitting, whatever) to the problem at hand. Incidentally, this is also a neat trick for when your characters are facing problems that they don't know how to solve.
If you are more of a visual thinker, have you maybe tried drawing a story map? Not all plots move around in space as well as time, but even if your characters aren't literally moving from place to place they still have to progress through some kind of process, right? Something has to happen to them that changes them fundamentally.
Try taking a big sheet of blank paper and about three or four different colors of pen. Use thick black lines to mark the parts of the story that are both already written and crucial to the plot. Then use other colors as necessary to fill in bits that you wrote, or things that you know need to happen but haven't written them. Use arrows to connect them together, like a flow chart. Then take a pencil and start pencilling in possible solutions for the blank spots.
Example: in blocks 1 & 2 the hero and heroine meet, and initially dislike each other. Block 4 is the hypothetical point where they're supposed to realize they're in love. In the blank space where block 3 would be, you pencil in some possible scenarios that would help them transition from disliking each other to grudging respect -- like the hero helping the heroine with a very embarrassing personal problem, without expecting compensation.
If you're not a very visual thinker... Well, what are you good at? What do you like to do? Try to adapt a problem-solving style that you're already familiar with (jigsaw puzzles, knitting, whatever) to the problem at hand. Incidentally, this is also a neat trick for when your characters are facing problems that they don't know how to solve.