Freelance writing is not easy. The bidding. The editing. The actual writing. It’s a complex process and you don’t have any backup.
You’re in charge of everything from communicating with clients to paying your own taxes. It’s a lot for one person to do, not to mention you have to make enough to pay the bills.
So what is a freelancer to do when they have five or six concurrent projects for which something needs to be written almost every day?
It’s hard enough writing 5-10 pages in a single day, but what if you have four separate projects that all require upwards of 5 pages in a single day? The mere act of transitioning between one type of project and another will slow most writers down more than any outside distractions ever could.
To help with those messy, over-scheduled days, here are a few strategies I use to transition rapidly between tasks as a writer:

Prep the Materials

Get everything ready to write. Create the documents, format the text, gather your research and lay it all out so that all you need to do is open the document and start writing.
It might not seem like much, but if you remove half of the tasks that are required during transition, you can greatly increase efficiency in those transitions.

Time Your Breaks Between Transitions

If you’re like most writers, you take your fair share of breaks. Sure there are those long streaks of productive time every morning and afternoon (or after midnight if you’re like Micah, my business partner), but you probably also get up every hour or so and take a breather.
Time your transitions to coincide with these breaks. If you can wait an extra 20 minutes for lunch so that you finish the first task, perfect. The alternative is to stop writing, take your lunch break, come back, dawdle for 10 minutes, finish the remaining 20 minutes of writing, and then spend another 15 minutes dawdling as you transition between tasks.
If you can wait 20 minutes for your lunch, you can eliminate that 15 minute transition.

Clean Your Compositional Palate

Recently I had two projects on my docket, each requiring some writing on a daily basis. One was for a series of short reviews of apps for the iPhone. They were light-hearted and short – very easy to write. The other was a series of dating articles and mini-guides that were written in concise language, but required a VERY specific state of mind.
I started each day with the dating guides, but by afternoon it was NOT easy to switch it up and write about iPhone apps.
So I started writing something silly in between. Blog posts, comments on other blogs, forum conversations – whatever would cleanse me of the dating advice mindset I had been in all morning.
Do the same and make it easier to switch between tasks.

Change Venues

When I work in Manhattan, I tend to move around a lot. Either because I’m hungry or because I need to use the bathroom and don’t want to leave my computer unattended.
As a result, I work in three or four places over the course of a day. Bookstores, coffee shops, Whole Foods, and restaurants (sometimes bars).
I make sure that I don’t leave any one place until a task is completed, however, so that I can transition more smoothly between those tasks by taking a short walk.

Split Your Day Up

If you can’t cleanse your writing palate as easily as I do or you simply don’t feel like changing venues, consider breaking your day in half. Go for a long walk midday, have lunch with your significant other, go to the gym, or watch TV for an hour.
Break things up enough that you feel like you’ve been away from “the office” and can start fresh. Avoid big meals at lunch if possible so you can stay focused.
Some people have a harder time with this than others. When I started writing full time as a freelancer, I would turn my schedule upside down to avoid transitioning more than once or twice a day.
Today, I regularly jump into and out of the middle of a project depending on who is working on it. Last week I had a day on which I wrote content for six different clients. I don’t recommend it.
But if you have a system in place, know what you can reasonably get done in a day, and transition rapidly, those shifts don’t have to kill your productivity. It takes time, but you’ll learn soon enough how to make it work for you.