Maybe it’s just me, but sometimes I feel like writing is rather like acting. In order to be great, you have to be willing to make a fool out of yourself. Now actors, don’t be offended, but the stage and screen require a certain dose of silliness to be authentic; I find it is the same with writing. To write empathetically, to write from the heart, you have to move past fear and give yourself over to your most ridiculous fantasies. That’s not to say you shouldn’t be afraid–you bloody well ought to be–but writing is an outlet for insanity, and thus deserves to be indulged.
So, with that attitude in mind, try your best to write bullshit. Don’t allow your brain to censor your mind. Don’t be afraid to write stupid things, or impossible things, or mad things, as long as you do write. Part of the fun of writing is just that: having fun. There are no right or wrong answers on the page. There are only words, and what you choose to do with those words is your gift and your legend, so set your plans and your literary expertise aside for awhile and just let the bullshit flow. After all, there’s always time to go back and revise. But restricting your own imagination to the confines of what you feel or have been told is appropriate defeats the entire point of writing; without putting those organic, crazy, unrefined thoughts onto paper, you have no base to build on. How can you edit something physically if you’ve already edited it mentally?
Take my advice: write bullshit. Get it out. Don’t try to tame your imagination. Let it do what it wants. You can worry and fuss about the details later.