A religious daily word-count does not make you a writer
1000 words a day may make you feel like a writer, but a 1000 words of crap just makes you a crap one. Writing isn't just about producing words – it's about creating stories, developing characters, imagining worlds. The words that reveal all that are just the icing on the cake. Prose, no matter how lovely, is just prose – without character and narrative to drive it, people will tire by paragraph 2.
Sometimes you need to do nothing
I'm the first one to tell you to maximise your writing time, but sometimes you need to just shut-down, wander around, and empty your mind. Clear the air, clear some space, give yourself a breather and day-dream; people watch, observe the world around you – with no more agenda than being at peace. Get in touch with yourself and yourself within the world. This will not only re-charge your imagination, but give you an opportunity to remember what it's like to just observe and feel.
Keep your head in the clouds while your feet are on the ground
Or vice-versa. Sometimes I get so tied up with the human-condition and how to write about it that I forget that some of the best stories are just totally out there – Alice in Wonderland or The Wizard of Oz for example. Don't cramp your imagination too much with reality, and likewise, if you're a dreamer, don't forget to keep it relevant.
A character driven piece is no excuse for a crap story
Disappointed Reader: What the hell is this? The character doesn't change, there's no story or narrative propulsion. Nothing happens. In fact, if I wasn't married to you, I wouldn't have got beyond page one.
Bone-headed Writer: Yeah, but that's because it's character driven.
A difficult subject matter is a difficult sell
No matter how scintillating your narrative is, certain subjects are going to turn readers off. No one is going to read your great story if they are going to put the book down as soon as they read the blurb.
Pants now, pay later
So, you need to develop character, construct a plot, define a setting, hone dialogue, then have a powerful voice and compelling narrative style to reveal it all? Scary. Far easier to just crack on with the manuscript and leave all that to your natural-born genius, luck, or later.
And you know which one it's going end up being.
Ernest H. said that the first draft of anything is shit, but you could always try and make it a little less shit with a little more forethought.