One of my favourite topics!
...not sure if I'm being sarcastic or not. I do like talking about it, but I fear people don't like what I have to say about it. I guess I'll find out what people think here?
I don't believe in writer's block. The term is a vague concept which encompasses way too many problems one could have with writing. External or internal. From fatigue, lack of inspiration, or a plain "I don't want to work on this part". My biggest problem with using the term "writer's block" is people ask for help when they have it and it's impossible to think of what is truly applicable. Not without knowing the underlying issue.
So if I had to answer the question: what helps me is determining what the specific block is. When I was younger, a lot of the time the answer was "just write", because the problem was a lack of interest in starting which would go away after I got a few paragraphs down. Sometimes what I wrote might not have been the best, but hey. I like rewriting and editing more than writing initial drafts anyway.
These days I have so many health problems that my blocks tend to be something I can't force myself through with writing, taking in old/new media, or taking a walk. I have to inhale some ibuprofen and shut my eyes.