From time to time, I cultivate surprise and suspense into a chapter in a total surprise to me. I'll begin to write the chapter, knowing how I want it to go, and once I actually get to write it, it turns out totally different than how I imagined it would turn out. The characters take over themselves and run free.
For me, myself, I need music in the background to be able to write well. Others need pure quiet. For me, as the music flows, my muse begins to run. The characters take over the scene and even surprise me. Believe me, you have to be totally relaxed but have your characters right there with you before you can write well. As the music flows, my characters begin to work the scene, taking over the keyboard with their own lives and living them in real time. I love when this happens. It's the greatest feeling in the world. I'll re-read over the chapter and marvel at what I've written.
I believe in writer's block to a certain extent, but I truly believe you can overcome this by bringing your characters front and center, right there with you, and let them roam free. Try it. I guarantee you'll overcome writer's block.