If you're thinking about DIY or DWO film distribution, you really must read the distribution bulletins on Peter Broderick's blog. For example, read what Peter Broderick has to say about the strategy employed by James Colquhoun and Laurentine ten Bosch, the husband and wife team behind the feature length documentary Food Matters. These first-time filmmakers used a hybrid approach to distribution (175,000 DVDs sold and counting) – "[C]ombining direct sales, online partnerships, and distribution deals. Offline screenings have supported online sales. Online marketing has supported 3rd party retail sales."
One lesson from Food Matters is that you shouldn't wait too long. As Film Collaborative founder and consultant Orly Ravid says: "Part of your distribution plan should include how long will wait before you start distribution... It is no longer enough to hope for distribution and sit and wait."