Suggestion for course creation

Happy,

I was in need of some suggestion from the community. I am new to course creation. And this is what is happening with me. When i screen-cast the video and write script for that video. For example if my video is around 7 minutes and when i write script, record and edit the final audio is around 3.5 minutes and video is of 7 minutes. It happens always the script become shorter and screen cast is very long and its leads to produce unattractive final video.

Please suggest how can i fix this and what are the best process & practices for course creation.

Thanks and Have a nice day to all.