Writer's Block continues to be a frequent topic in the Improve Your Writing club, and I've noticed that the causes usually fall into one of four categories:
1. NON-WRITING-RELATED STRESS
If your personal life is taking a hit, the problems tend to loom large in your mind. It crowds out everything else, including creativity. It's quite difficult to write stories when all you can think about is the stressful situation. The solution, in this case, is to deal with the situation, or find ways to relax. Forcing yourself to write under these conditions will only add more stress, so don't.
Try reading for fun, playing video games, or meditating. Or you can do what I do and pour your angst into words. Write about your problems in a private essay to yourself. Vent as vehemently as you want, because no one will ever see it. Curse a lot! It'll act as a form of release for your pent-up stress. Then later, when stress levels have decreased or at least become manageable, you can give creative writing another try.
2. "WHAT HAPPENS NEXT?"
Sometimes we lose sight of our story. We finish a great scene that inspired us, and now... nothing. My first question to you is, do you know how the story is supposed to end? If not, then that's where you need to focus. It doesn't have to be a specific scene, just an idea. For example, the humans thwart the alien invasion, or the two main characters finally hook up, or the orc leader is defeated in an epic battle. You have to know where your story is headed before you can make progress. It's like driving around without knowing where you're going. You'll likely end up circling the block, going nowhere.
You know the ending? Great! Now you have a beacon in the distance. Now we can start filling in the blanks. My favorite method is working backwards and coming up with a bunch of maybes. Let's take the orc battle plot line as an example. Our main character (let's call him MC) is now in training and you had fun writing that part. Now what? Okay, the orc leader lives in a fort clear on the other side of the land. What does MC need to learn in order to defeat him? Maybe it's not just the obvious battle skills. Maybe it's self-confidence, or trusting others for help. Okay, how can MC learn the things that can't be taught in a training room? Maybe he learns these things on his way to the fortress. What kinds of situations might come up? Maybe he defeats a troll all by himself and builds confidence. Why is he all by himself? Didn't he leave with a team? Maybe they were sleeping.
Keep going like this, asking yourself questions and working backwards. You'll eventually see your story start to form from the nebulous ideas previously floating around.
3. PERFECTIONISM
To quote Tina Fey in Bossypants, you don't want to be that kid at the top of the water slide overthinking everything. At some point, you just have to take the plunge. Many writers cannot stop editing their first chapter. "It doesn't seem right!" they cry and dive back in again, tweaking things, trying to make it perfect. There's nothing wrong with improving your story, but not when it comes at the expense of finishing your story. Don't do this to yourself. Written words are not permanent. You can always change them later. Stop obsessing and move on. Once you finish the story, you may need to go back and change a few things earlier in the story anyway, so all your effort trying to perfect it will be wasted.
Writing is done in stages. Stage 1 is brainstorming and/or planning. Stage 2 is the first draft. You spill your brains into words and you keep going until you're done. Don't worry about right or wrong, just go. Stage 3 is when you finally start revising and fixing things. Stage 4 is getting outside opinions on what needs fixing. Stage 5 is fixing those issues. I go through Stages 4 and 5 repeatedly before declaring a final draft.
4. BURNOUT
If you keep banging your head against the stress of #1, or getting stuck in the endless circles of #3, you'll eventually reach burnout. This is when your energy is spent. You are sick and tired of your story. You can't stand it anymore. It sucks. Writing sucks. Everything sucks, including yourself. GAHH!
Stop. You need a break. Writing is supposed to be fun. If it's not fun, then you you're doing it wrong. Don't cry over your lost muse. She isn't lost, just tired. Take a vacation from writing. Don't think about it. Do other things that bring you joy. Go fishing, or knit scarves for the homeless, or level up your barbarian until he's strong enough to wield the Mighty Axe of Ass-Kicking and go trounce the demon king. Do things that make you feel good and build your confidence. When thinking about writing no longer makes you sigh or sweat, then you can give it another try.
Votes help writers like me break through writer's block, because it builds confidence. ;)