Do's and Don'ts of writing a first draft?

Don't over-analyze your writing. At the first draft stage, I find it's best to focus on getting the story down so I don't lose my train of thought or momentum.

Do feel free to follow the story where it's leading you, even if it's not what you initially planned.

Don't obsess over details, like how long your chapters should be, what character x's name should be, what font or format you're typing in.

Do work on it as much as possible to keep the story fresh in your mind and your creative juices flowing. Keep a note pad or something handy when you're away from your writing to jot ideas and thoughts.

Don't worry yet about how good it is, whether it's publishable, etc. There will be plenty of time for that later.

Do have fun!

For a FIRST draft, there really aren't any don't---except that you shouldn't fall in love with how it's written. I'd put in more than you know you'll end up with because you'll probably cut out a lot later.

Another word of caution---don't share it with others at this point. You'll get too many people telling you which way the story should go. It's yours. Own it.

Every writer finds the method that works for her. My way is to do some character work first---create a history and description of each person. Maybe make a map of the place where the story takes place. And describe the situation at the beginning of the story. For example, if the story is about a business office in the city, you could outline how the business is doing, who the customers are, how many employees they have, etc.. That way you can keep your facts straight and not have to keep track of it as you go.

Good luck

Just start writing and don't edit yourself as you write. (I have a tendency to do that.) Just write and go with the flow.

Use a word processing software. It will make it easier if you want to cut and paste.