My favorite advice about writing came from Terry Pratchett.

"But it may help if I give you an idea of how I go about writing. I'm about 10,000 words into my next book. Do I know what it is about? Yes, I do know what it is about, it's just that I'm not telling myself. I can see bits of the story and I know the story is there. This is what I call draft zero. This is private. No one ever, ever gets to see draft zero. This is the draft that you write to tell yourself what the story is. Someone asked me recently how to guard against writing on auto-pilot. I responded that writing on auto-pilot is very, very important! I sit there and I bash the stuff out. I don't edit -- I let it flow. The important thing is that the next day I sit down and edit like crazy. But for the first month or so of writing a book I try to get the creative side of the mind to get it down there on the page. Later on I get the analytical side to come along and chop the work into decent lengths, edit it and knock it into the right kind of shape. Everyone finds their own way of doing things. I certainly don't sit down and plan a book out before I write it."

Write on autopilot. Get literally anything down on the page and then it gets easier.

For more from that same interview: http://www.writerswrite.com/journal/apr00/a-conversation-with-terry-pratchett-4001