Focus on super-specific how. Do not spend a lot of time on the “why” or the “what.” Also limit how much you talk about your own personal experience. Use your personal experience for color and personality, not for core instruction.
Try to limit yourself to one key point per slide. If you have multiple points per slide, consider showing them one at a time. Students will pay closer attention and feel like they're getting more from the presentation when slides change or advance with new key points. It also helps keep you organized, on track, and focused.
<aside> 💡 See: Secrets to Better Slide Design
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Make your key point the headline of the slide. Think in terms of what people should remember after the presentation is over. Rather than a slide headline that says "Plot," instead say, "Every plot needs reversals." Do not bury or make your key point a secret. For online teaching, spell out what the point is on the slide, then discuss and elaborate on that point.
Get to the good stuff immediately. The first five minutes of your online class is critical to gaining and keeping student attention. When you teach in person, you may spend the first 5-15 minutes on introductions, ice breakers, a discussion of your own work, your background, etc. DO NOT DO THIS for an online class. It is deadly. People's attention will wander. They'll get bored and wonder when you'll actually teach them something. Dive into the curriculum right away. Even better, start with the biggest mistake, or biggest lesson writers have to learn about your topic, or something that's counterintuitive or attention grabbing. Drama helps. You want students to feel like they are in for a meaty presentation and that they might miss something important if they don't stay focused on what you're saying.
Concrete examples work wonders. If you've written for magazines like Writer's Digest, you know the importance of examples. Good versus bad, right versus wrong, weak versus strong, original versus revised. Use examples liberally. You can make them up, but examples of published work (for "good" examples) are recommended as well. Keep in mind diversity when choosing your examples—aim for a mix of genders, races, identities. You can use your own work, too (but don't use your own work exclusively).
When in doubt, err on the side of focused and formal. While everyone appreciates an instructor who is relaxed, flexible, and conversational, online students benefit most when you can move through the material in a structured, predictable and focused way. Sometimes there is a fine line between relaxed and disorganized. Try to limit tangents or digressions; you'll lose students if you stray too far or too often. A good phrase to memorize: "I could say more on X, but we have other things to cover first. We can discuss this more during Q&A if there's interest." The best time to stray from your prepared presentation is when taking questions.