In her post for ProfHacker, Amy Cavender offers some tips for screencasting. Two of the best are time limits and scripts.
Cavender suggests that screencasts should be two to four minutes. in general, I would agree, but the screencast can be longer if the circumstances call for it. Some instructors use screencasts for lectures as part of blended learning. I have used screencasts for assessing student work, and this sometimes goes beyond the ideal “four minute” mark. For tutorials and student presentations, two to four minutes is ideal, but time limit should be determined by the function of the screencast.
Cavender also suggests a script. I think a script is great, especially, as she offers, if you plan to create a SRT file with captions. When I first started doing screencasts, I used a full script, and spent so much time on the script that it added labor to doing the screencast. I recommend using an outline, much in the way some opt to use an outline when presenting a paper rather than reading the paper. It makes the screencast seem more natural and less stilted, and more effective since you are not spending time perfecting a script.
I would add one additional tip on takes. While one may be tempted to barrel through recording the entire screencast in one take, I would recommend breaking it up. I use Screencast-O-Matic, which allows you to pause the recording and truncate so that you can eliminate parts you do not want to use.
Amy Cavender. “Simple Screencasting Tips.” ProfHacker. 11 Aug 2014. Web. 15 Aug 2014.