By "writer's block" I'm going to assume that you mean "outline block." Because if I have an outline, I can always write. If I'm writing by the seat of my pants, I sometimes freeze, not knowing where to take the story.
I have no emotional or practical tools to fight outline block. Zero. I just suffer magnificently, reach a point of true despair, officially give up the profession entirely in my mind, and then--usually while jogging or walking or taking a bath or cooking while not listening to the radio--something will unhook in my brain, and a key piece of the outline will come to me.