SEO Guidelines

Here’s a general, beginner-oriented mostly, common sense rules for SEO. It’s the first steps before and after purchasing a domain:

URLs should be keyword optimised and user friendly (avoid *+%! characters).
Use hyphens instead of underscores to separate words within the URL.
URL length should be under 100 characters.
Keep URLs lowercase.
Non-www versions of URLs should redirect to the www version (e.g. example.com should 301 to www.example.com).
Non-secure http versions of URLs should redirect to the secure https version (e.g. http://www.example.com should 301 to https://www.example.com).
/index.php or /index.html style URLs should rewrite to www.example.com.

Include both HTML and XML sitemaps to help users and crawlers discover your site’s structure and content (sitemaps should automatically update with the addition/removal/editing of pages).
robots.txt or meta robots tags should only block select directories/pages as required.
Content should load within HTML (crawlers can have trouble with JavaScript etc.).
An editable rel="canonical" tag should be implemented on every page.
Content should still be visible with JavaScript and CSS styles turned off in browser.

Implement any structured data (Schema) elements relevant to your website including breadcrumbs, event, organization, local business, ratings/reviews, price, product, images for eCommerce etc.

Implement Google Tag Manager across all pages incorporating Google Analytics and, optionally, Google Ads Remarketing codes as applicable.
Implement Google Search Console and Bing Webmaster Tools.
Redirect users to a “thank you” page after any form submission.

Note that, in 2021, web standards count more than ever. A well-formed web document will help your site rank better.