I won #NaNoWriMo with 50,032 words. I'm only about two-thirds of the way through the story, and I have only a vague idea of how to end it, but I made the total word count.
I learned a few things along the way:
1. I find it a lot easier to write if I have a solid idea or scene already formed in my mind. If I have a good solid scene in my head, I can whip out 500 words in no time at all, but if I only know I need to write a scene or two to get to that solid idea, it takes me a lot longer.
2. But if I don't have a good idea of what to write next, I'm often pleasantly surprised by my own creativity. It's not unusual for characters or tidbits of information to seemingly come out of nowhere, and these surprises are often the most interesting thing I wrote that day.
3. Short term goals are easier to achieve than long term goals. I've been hearing variations on this for years, but I now have solid, personal experience which proves it, and which has led to a shift in my thinking. NaNo showed me how to write 50,000 in 30 days by breaking it down into a daily word count. I'll will probably continue to approach my writing in the same way.
4. I don't need to turn off my editor. I've heard that a lot. It seems to be one of NaNo's common bits of advice--turn off your internal editor, and just pump out the words. I'm not sure that advice is completely valid. I think it should be something more along the lines of, "Learn to work with your internal editor." If you work with that editor, your writing will be better--unless you listen to everything he or she says, and then you'll just want to stop writing. Listen, but you decide if it can wait until you know how to fix it, or if you can fix it now without interrupting your flow.
5. Support systems help. It doesn't have to be much. Just tell your friends and family, especially that nosy aunt who will ask you about it every day. Or join a group online, or in your local community, and offer support to others. You'll be surprised how much positive motivation can come from this.
6. If you want to be a writer--just write. Don't worry about what. Buy a journal and a pen, and fill a page every morning. Start a blog, and spill random chatter all over it--frequently. Or annoy your friends on Facebook and Google+ with your lousy poetry. Maybe you'll loose some friends, or maybe random strangers will want to read it. What matters it that you wrote something.
7. You can't write all of the time. You shouldn't try. It you are stuck, and sitting there wishing you knew what to write, play a video game or watch a movie. Take a break when you need to take a break. Or, if you want to write, but don't know why you can't, write something personal--something you would never admit to another person--and then destroy it if you need to.