A few weeks ago I recorded my first screencast, and this week I've been working on another one, and so I thought I'd share some "secrets" I've discovered in the process. While I'm by no means a professional, I figured that sharing this might help others with their screencasts, and prompt folks to share their tips too.
Software and Equipment
I use gtk-recordmydesktop to record the video. As much as I am a KDE fan, the KDE/Qt apps don't seem to work on Kubuntu.
Currently I'm recording my audio on my cellular phone, due to what seems to be a hardware issue with the microphone on my PC. I'm using Audacity to clean up the audio after I've recorded it.
I use Kdenlive for video editing. It's the Window Movie Maker of Linux, but it works very well for most consumer-level video editing. It has its quirks, but out of all the tools I tried, it has best interface and was the least irritating.
Of course nothing beats a good microphone, but most microphones are sufficient for the purposes of a screencast, so don't go out of your way to buy a fancy and expensive one.
Useful Tips and Tricks
The single most helpful tip I have received is to record your audio and your video separately. This allows you to concentrate on recording each part without the other interferring, and results in a far better screencast overall.
More of a "must" than a tip is to write a script. First write up the steps you are going to perform in your video, and then expand that into a full-blown script of what you are going to say.
Practice both your steps and your script numerous times. It is quite helpful to have someone else read through your script while you run through the steps, to see when you need to slow down in your script, and when you need to wait between steps.
Record your video first, it is usually the slower of the two. Read the script out loud as you record the video to help pace your actions.
When recording the audio, play the video so that you can speak at the right times. It's also easier to speak at the right speed when you're watching the video.
Wait a little bit before starting to run through your steps, or when starting to speak. Do the same once you're finished. This gives you a bit of extra video and audio to get rid of unwanted visuals and sounds. No one needs to see you opening gtk-recordmydesktop to stop it.
Use this extra bit of "silence" in your audio recording to remove ambient noise using the noise removal tool in Audacity. In my particular case, I have the sound of my computer and my servers in my study, and therefore in the recording. By selecting a bit of this white noise, and using it as the noise sample in Audacity, I was able to remove the background noise and have a clean recording.
To remove echo from your recording, use heavy fabrics like blankets and towels to cover the walls and ceiling of your room. In order to do this in my study, I ended up creating a "tent" from a blanket hung from various bits of furniture. It looked weird, but it got rid of the echo!
Use a nice instrumental piece of music on a very low volume to provide an audio backdrop to your voice.