Stick to the topic.

FORBES: Peggy Post on Workplace Etiquette

Here at Mixed Signals when we get a lot of comments on a post we like to stick with the topic (or, depending on your point of view, flog it to death).

NPR: First Couple Divided Over National Anthem

The rule of thumb I try to follow when creating internet videos is this: stick to one idea, one topic and one main point, and say it as briefly as possible without leaving out all of your good stuff.

FORBES: How long should an Internet video be? -media training