When it comes to writing, there are people who plan their plots meticulously (plotters), those who do no planning whatsoever (pantsers), and then the majority of people who fall somewhere in between.
On this sliding scale, I find myself much closer to pantsers than plotters. Generally I’ll have an idea about the characters before I start out, a point A, and point B, but sometimes, it’s not even that much. Sometimes it’s a general concept and a title. If you’re shooting for 5,000 words, that’s a pretty good start. Writing longer works like this can be tricky.
My advice is about every 20,000 words, stop and edit. Yes, this goes against conventional wisdom; however, I’ve found at about 20,000 words in I’ve painted myself into a few corners, and also have a much better grasp on the characters and story. I go back and fix the paint, and start layering in those details which help my story come alive.
Even if you are a plotter, going back and rereading your work (and let’s be honest, if you’re doing that you’re probably editing it too) while writing can be helpful. Characters/storylines tend to shift once you get them out of your head and onto paper. Worried that Bob’s coming off all tough and manly, so this scene where he’s crying isn’t going to work? Reread your manuscript, keeping that in mind. Flag the places where he’s acting macho and see what you can do about them.
For pantsers, it’s one of the best solution when you get lost. It gives you a better feel for your world and characters, and just connecting with your work like that will often give you ideas of how to proceed.
So, the next time you get stuck, try editing what you have and see what happens.