One of the most common questions I get when I do school and library visits is how I deal with writer's block. My answer is not a popular one, but it remains the same.
I don't necessarily think writer's block exists. If it does I haven't experienced it yet, so if / when I do I will come back to this post and eat some crow. For now I call it procrastination, something all writers are familiar with, and I think procrastination itself is a symptom of fear.
I always have ideas, I just don't necessarily know how to execute them. Typically if I've hit a scene that is dragging or I simply don't know what happens next, it's because I don't know enough about my topic to deliver. For example I was recently writing a scene that took place in the back of an ambulance. I had no idea what the medics were wearing, what machines they had back there, what kind of language they would use to communicate with each other. It took three days and the exchange of over 25 emails with an EMT friend in order to finish that scene - which is only two pages long.
That's a snail's pace, and incredibly frustrating. But diving into the research for the particular disease that afflicts my main character was enlightening in more ways than just medical terms. I'd reached the halfway point on the manuscript and was wading into waters that went over my head. I vaguely knew what I wanted to have happen in my plot, but knew I needed a juicy subplot in order to avoid a saggy middle.
Some research provided me with exactly what I needed. Just a few lines out of a medical journal provided a simple fact - candidates for heart transplants wear pagers to be alerted when a heart that matches them is available - and suddenly I had a supporting character, a subplot, and an entire backstory for her that would could nicely draw out a few of my main character's less-lovely characteristics.
One line of research provided me with enough material to fill at least a quarter of the gaping back half of my book. Being a pantser isn't for everyone, and I know that if I were a planner I could have avoided this particular gaping hole of almost-writer's-block that stared me down last week. But I stared back, did some research, emailed some friends, and it flinched first.