Documentation:DIY Screencast/Record

Prepare your computer and your environment. Spend some time clearing your browser cache and desktop of unnecessary files, personal items, folders and icons. Remove visible bookmarks from navigation bar, disable pop-ups and test-run your web applications. If possible, install a second “clean” browser on your computer for screencasting.
Prepare any images, other video files, and audio files you would like to use in addition to your screencast.
Consider the use of the webcam talking head - do you need it? Does it support your goals? Is it distracting?
Be prepared if you need to move around the screen by positioning the screen recording area appropriately and making use of tabs and the pause feature.
Be sure to outline what students will learn in the screencast and then recap or summarize at the end.
Set the size for your video. 800x600 is a good resolution, which seems to be just the right compromise between bandwidth and clarity of the presentation. YouTube and others now offer HD resolution and wide-screen formats too, but not everyone else does yet, so 4:3 formats are probably best for now.
Make sure you have water available for speaking.

Reduce echoes by filming in a room with soft surfaces such as your living room. Reduce or eliminate electrical sounds such as computer fans and other appliances.
Avoid rooms with echoes or fans (even imperceptible fan sounds may be picked up by an external mic).
Test your sound for quality in your location with equipment. Improving the audio even marginally will far improve the perceived quality.
Prepare your lighting if you will be using your webcam.