Be doing something related to writing.
Sure you're not deep into your fifth cup of coffee, eyes bugged out of your head because you've been staring at the computer screen for hours but you can be doing something.
Edit something, continue to build your reader platform, outline your next book, get to know your characters better by creating a history for them. Anything. Hell even reread one of your favorite books to inspire you.
Remember, you're in the long game, the Iron Man Triathlon of writing. It's a long road ahead of you but the key is one step at a time down the pavement.
Happy Writing!