From my interview with Kay Reindl
Writers tend to do one of two things -- underwrite, and overwrite. Sometimes it's easy to include too much information. Generally, you'll see this stuff get cut in editing. In network TV, it's actually different to underwrite the plot, because the executives will be confused and they'll tell you!
On
Charlie Jade we had a showrunner who
hates exposition, so he constantly pushed us to write more elliptically. I think there's a writerly prejudice against overwriting: no one likes to read something they already know, least of all staff writers. It's probably a mistake to underwrite on a show, if you've got good editors, because they can always cut out explanatory dialog that proves to be unnecessary, but if the story isn't clear and you've got no expo to fall back on, then you're stuck.
You need to make sure your story works, is told clearly, and that your characters' motivations are clear and make sense. If something's not working, ask yourself why it's not working. This seems silly and obvious, but putting a question to yourself can actually help. If your instincts are saying that something's wrong, something generally is.
That's one of the hardest things to do, fix things you might be able to get away with. Most writers I know are more interested in whatever aspect of the story really interests them, and would rather not stop to fix some problem that's nagging them in the back of their mind. I'm not sure I entirely agree with Kay, though. Sometimes the fact that you only have a nagging feeling that X is wrong is because it's actually Y that's wrong. What you feel is the problem may not be the real problem. To figure out what's really wrong usually requires either time or another writer's eye.