|Sitting there staring at the white space.|
You go back and read what you've already got, hoping that will get the creative juices flowing. Nada.
You look at your outline. You look at your notes. You turn on your favorite writing music. You try to get back the feeling you had when you first imagined the story. Still nothing.
So you decide go online to see what other writers do when this happens to them. And somebody tells you that the last hour of your life didn't happen. "Writer's block isn't real. Therefore, you don't have writer's block. Therefore, just get back to writing."
I don't know about you, but articles like that don't help me. Telling me I'm not experiencing what I'm experiencing has never made the problem magically go away. If it did, I'd start telling everyone I met that there's no such thing as sickness or pain. "It's all in your head. Or maybe you're lazy or looking for attention. Just get back to feeling good."
Writer's block is as real as a sunset. It could be argued that a sunset is only a combination of conditions (moisture in the atmosphere and the viewer's position relative to the sun) but that doesn't make it any less of a real experience for billions of people every day. If you're experiencing writer's block, then writer's block exists. It's a real problem for you that requires a real solution. "Just get back to writing" doesn't cut it. You already tried that.
When I was in school I had trouble with math. If I didn't know the solution to a problem, my strategy was usually to sit there at my desk and "try hard." Trying hard involved staring at the page and tightening my facial muscles until they hurt. It was exhausting. It made me hate math. And it didn't work. To make matters worse, I felt guilty because the fact that I hadn't come up with an answer obviously meant that I wasn't trying hard enough. Now I save myself all that trouble by simply analyzing the problem and figuring it out.
The same strategy works when I don't know what to write. I take a good look at the problem, and once I understand it, the solution is usually easy to find. Sometimes the story doesn't work, and I need to go back and do some revisions. Sometimes I'm distracted or not feeling well. The reasons for my writer's block vary, but once I figure out what's keeping me from writing this time, it's just a matter of taking whatever steps are necessary to eliminate the cause.