Pick a starting date such as the first day of the month. Give yourself a week or two before your starting deadline to think about what you want to write about. Jot down notes about the characters, the basic background of the story and a brief outline of the plot.
Start writing on your starting date. Do not worry about editing, just keep writing. Writing a novel in 30 days is about writing the first draft -- you can make it a masterpiece later. Do not worry if you start writing without a plot. Ideas will come to you while you are writing.
Write every day. Have a goal in mind for the amount of work you will complete every day. This can be a minimum word count or a minimum number of hours writing. Aim for your goal every day. Take a day off only if you really need it, and do not take more than one day off consecutively.
Turn off the TV and disconnect from the Internet, email, instant messaging and any other distractions. If you can, write in a location or on a computer that doesn't even have Internet access. Writing a novel quickly requires concentration and dedication, so you need to be able to focus on writing for hours at a time. Reserve an hour or two a day for online activities and television after you've accomplished that day's writing goals.
Write toward your total word count. Most publishers consider a manuscript of about 70,000 words to be a novel. Aim to write about 50,000 words in 30 days and you will have a solid draft from which to craft your finished novel. Try not to think of the huge number of words required. Continue to write every day, even if it's only 100 words at a time.
Finish your novel on the last day of the month and celebrate. Give yourself a couple of weeks off, then go back to your novel and start rewriting and editing. This part of writing a novel may take much longer than 30 days, but the first draft you wrote in 30 days will supply you with a solid base from which to craft your finished novel .