1st order approximation: what you say and do doesn’t really matter and has no effect on student learning.
2nd order: what you say and do strongly affects how students feel… how they feel about you, where they are, who else they are with, themselves, etc.
3rd order: how students feel about all that stuff affects what they do, but also how they go about doing those things, and how the things they do at one moment relate to other moments and other things.
4th: what there is to do depends on what an environment makes possible for doing. And since not all environments are equally good for all kinds of doing, a thoughtfully and carefully arranged environment is needed if you care about what it is students might do and how they might go about doing those things.
5th: every once a while students will be doing certain kinds of somethings and feeling certain kinds of ways, and what you say will matter. It will be consequential to what they do next…
Conclusion: spend most of your time on preparing that environment and on nurturing those feelings so as to create a few moments here and there where what you say matters. Try not to fuck it up. But you probably will, at least some the time, and that’s ok too. Just get back to working on the things that matter.