When writing, there are times when you know what needs to happen next, but it just isn't happening. I have found that's a good time to pick up shop and move house.
My interpretation is that "this scene is hard to write" really means "this scene isn't happening in the right place," or even "this scene isn't happening at the right time." There's an excellent chance that you have the right idea and the wrong context.
Not always, of course; there's also the chance that you're thinking of something that does happen, but which should not happen on stage. Maybe the scene is too pedestrian to go wasting either your time or the reader's on conveying it, but I would propose that this is a fairly rare occurence. More commonly, you have set a scene at the grocery store when it needs to be on a mountaintop.
Recently, I literally moved a conversation to a mountaintop. The reader needs to know a few things:
- My character feels very strongly about his friends and family.
- He believes he often asks too much, or asks unreasonable things, of his friends and family.
- This is in spite of the fact that he is perfectly willing to do those things himself.
- His response to this kind of uncertainty is to pull away, ostensibly for the good of those same friends and family.
- This has harmed and continues to harm his relationships.
Now, there are a few ways I can convey this. I can attempt to show it, but I believe that would simply have too high a cost in terms of word count, particularly given that it's part of the foundation for his character and not something that needs to be developed in the course of the story. In contrast, I can have him think about these things, which is basically what I initially went with, but I believe that makes for boring reading. The last thought I had was to have him talk about these thins with someone else. That's the option I chose for the mountaintop version.
Specifically, my character--we'll call him Character 1--talks to Character 2 about a relationship with Character 3. To keep this from being boring, an event occurs which uses Character 2 to demonstrate the problem Character 1 is afraid of. In the end, I come away having achieved my goal and, hopefully, not put anyone to sleep.
The intended takeaway here is that it's best not to be afraid to reassess your progress and change course, frequently if necessary. If you're midway through a scene--or even if you are finished--and it just doesn't feel right, if it lacks the kind of punch you want it to have, if it doesn't flow properly from the previous scene and into the next, then feel free to pick up sticks and head someplace else with it.
Whether or not this is useful advice, I don't know. You probably need to have some instinct for when a scene does not flow, or when it is "hard to write," before this comes in handy. Maybe that's something I can get into later on.