There are different kinds of writer's block. And they require different approaches. When I'm not inspired to write, I try to read good books by new authors. I go to movies. I look at art. I make notes and give myself room to just absorb information and the work by others.
When I have a writing problem to solve, I try to take my mind off the problem by chopping vegetables or ironing. I actively change the subject.
I think that the type of writer's block that is most damaging is the kind that undermines my confidence, the kind that makes me think I'll never write anything worthwhile again. And that's the kind that causes me to give myself permission to write very bad first drafts...The thing I always remember is that there will always be more words. Sometimes it's good to lose a draft and be forced to rewrite the whole thing. That way you know that nothing is too precious.