1. Lighting
More light is better. If you're in a dark area, move towards a window or outside. There's a very inexpensive LED light that you can get from SIMA that's great for adding more light.
Check it out at http://stevegarfield.com/store
2. Sound
Getting better sound with a camera that doesn't support an external microphone is easy if you are aware of your location. Keep YOUR ears open when recording. I've seen way too many interviews conducted in the middle of a noisy show floor. Move to a quieter place, like a hallway or an empty room. You can always use an audio recorder in addition to the Flip and merge the video and audio later in an editing program. Plural Eyes helps do that automatically.
3. Editing
I love FlipShare. Makes it very easy to edit your videos. If you are on a Mac and want to move up to something with more features, try iMovie 09. It allows you to overlay video so that, for example, if you are conducting an interview, you can show the viewer interesting shots of what the speaker is talking about.
These tips and more are in my book Get Seen.
An edited version of these tips was published at My Life Scoop in the article, 6 Tips to Make Your Flip Videos Rock by Linsey Knerl.
Thanks to Jeff Esposito for sending me this HARO request.