INTRO: I'm by no means an SEO expert. At least not yet, however, my purpose is to help my friends at the developer community have some kind of guideline for properly optimizing their pages. I'll be using my moving company website as the example

LIST OF META TAGS THAT MUST BE INCLUDED AND OPTIMIZED FOR (IMO)
<title>Go beyond just cheap movers. An honest peer built moving service</title>
<meta name="description" content="A moving company based in salt lake county. We charge hourly, and remove all nonesense fees.">
<meta name="keywords" content="moving service, cheap movers, cheap moving companies, local movers near me, movers and packers near me, how much does it cost to hire movers, storage building movers, cheap moving, low cost movers">
<meta name="author" content="John Doe">
<meta name="viewport" content="width=device-width, initial-scale=1.0">

REASONS WHY

description: This one might not be so obvious to some developers. This metatag is absolutely vital for SEO purposes. This description is the one that shows up right below your page title in google searches.