You hear this advice a lot. And up until now, I didn't think I was following it; after all, I went through a six month drought of zero fiction.
The thing is, I have been writing! I write every single day, sometimes thousands of words, just not on what I would consider fiction in any way. I write journal entries in my livejournal, posts on forums, emails in my duties as NaNoWriMo forums moderator... every day, my hands are on the keyboard, tippy-tapping away. I log many, many hours a week at the keyboard, writing.
So I'm already in the habit. Now I just have to turn a fraction of that energy to actually writing creatively!