Grading in general

In general, broadcast courses lend themselves to standards-based grading. Attaching points to every little item can motivate students in the wrong way. Think of what your final outcomes should be and assess mastery based on those desired outcomes. 

Here are some excellent articles when it comes to think about grading. 
How to Grade Broadcast Journalism Students (Part I) by Michael Hernandez
How to Grade Broadcast Journalism Students (Part II) by Michael Hernandez
Frame of Reference: Fair and Balanced Grades by Janet Kerby
Frame of Reference: Fair and Balanced Grades  - Part II  by Janet Kerby
Broadcast journalism skills, objectives, and learning outcomes by Don Goble
Broadcast Lessons and Resources by Michael Hernandez
Five common mistakes in high school broadcasts by Dave Davis
General video rubric