Focusing on Enduring Understanding
Here is a graphic from Understanding by Design that is useful for designing online courses. What is important to include in a course? The classic pitfall of building online courses is course-and-a-half syndrome. Because online spaces are so elastic, it is tempting to stuff a course full of everything you think might be useful. However, too much material can obscure what is truly important. The best way to design a course is to focus on the core of what you want the students to remember, what Wiggins and McTigue refer to as "Enduring Understanding," i.e., the important, transferable concepts and processes that you want students to grasp. From there you can work outwards to include what is "important to know and do" and "concepts they should be familiar with."
Graphic adapted from Figure 1.2 Establishing Curricular Priorities in Wiggins & McTigue, Understanding by Design