Make a plan
Create a word count goal that works for you and establish daily or weekly word count goals based on your schedule. The official NaNoWriMo challenge has a 50,000 word goal, which would require around 1,667 words per day or 12,500 per week.
Write something every day--even if it's just a sentence.
Don't be deterred if your behind on your word count goals! The most important thing, and goal of the challenge, is to write and creatively express yourself every day. Short stints of writing, however small they may be, add up.
Spend your time writing, not editing.
NaNoWriMo is for creating a rough draft, editing and revising come later. The primary objective should be to get words written down.
Let the plot develop as you write.
Having a general idea of what will happen in your story is important, but significant time shouldn't be spent outlining or plotting.
Have a dedicated time every day to write, free from distractions.
It's important to get all you can out of a writing session and that means designating time for just writing, without the burden of trying to multi-task.
Do what works for you.
These tips may be helpful for some and completely unhelpful for others. You should prioritize doing what works for you and your creative process.