With text, less is almost always more. One thing to avoid—slides with a lot of text, especially if it’s a repeat of what you’re saying out loud. It’s like if you give a paper handout in a meeting—everyone’s head goes down and they read, rather than staying heads-up and listening. If there are a lot of words on your slide, you’re asking your audience to split their attention between what they’re reading and what they’re hearing. That’s really hard for a brain to do, and it compromises the effectiveness of both your slide text and your spoken words. If you can’t avoid having text-y slides, try to progressively reveal text (like unveiling bullet points one by one) as you need it.