Write it, write it, let the ugly baby come to the world
If you have a terrible idea or if you have a lovely idea that you cannot put it beautifully today, just write it anyway. Write it and you'll have the chance to re-write it.
Can't you do a great dialogue? Just let your characters talk, let them be boring. Hey make them chat about the weather, or how lovely the fire is burning.
Because after you get to do that, you have something to work with. You have a baby that you can feed, pamper, tell stories, let her, him, or whatever grow. Let your creature amaze you and take you places you didn't even know they ever existed.
But it has to be born first, ugly, dirty and all. Just do it. Tonight, you might be tired, do a few awful lines, nobody's watching.
Tomorrow the sun will shine on you, chipirón. <-- Evil youtube link, but the music will make you smile.