I don't get writer's block. Instead, I get writer's fear.
While the white page doesn't bother me, filling that page involves navigating strange territory. Even detailed maps and outlines warp in the act of writing. Settings shift. Characters refuse to be the people I imagined at the outset. This is wonderful: surprise is one of the best and truest parts of writing. But the more I press into new territory, the more the worries grow.
They start out logical: does this character make sense? Is this response authentic? Does this scene matter? Will my readers understand this story and setting?
But then they reproduce like tribbles in heat. I trip over them. They change character, become accusations. Your story's irrelevant. Pretentious. You don't know what you're doing. You don't have a right to talk about this topic. Give it up. And so on, and so forth. Fears fill the empty space in my head, and strangling characters, plot, and world.
Wrestling with fears is part of every writer's life, but I've been slow learning the wrestling technique. These fears feed on anticipation and attachment. Which means that tools designed to approach excessive anticipation and attachment can help with fear. Recently I've used a simple Buddhist meditation trick, which I think I first read in Tricycle somewhere: 'not-that.'
'Not-that' means confronting thoughts that arise during a period of meditation (and writing is a kind of meditation) and saying, 'not that'—this isn't the point, this isn't the problem, this isn't the focus of my existence. 'Not that,' said in silence or aloud, is a lot faster than arguing my fears into submission, and more effective: a few minutes' work can clear out a pile of emotional laundry, and free up time, and more importantly, mental and emotional space, that I didn't realize were occupied by fear.
Besides, it's fun. My plot sucks—not that. Nobody wants to read this story—not that. I should have gone with your other idea—not that. Let everything go, except of course for the act of writing. When I have a draft, when I'm editing, then I can invite all those concerns back in, and determine which are justified, and which aren't.
I don't expect this technique to work for everyone. Like all techniques, it's just a finger pointing at the moon. But if you find yourself stymied by fear, give this a shot, and see if it helps.