I produce a lot of content on how to make best of use of Sitecore’s Page Editor:
Improving the Page Editor – Blog Series
Part 1 — Uses for parameters
Part 2 — Sample data and HTML
Part 3 — Detecting Page Mode
Part 4 — Using placeholder settings overrides to change availability of compatible renderings
Recommended Practices Guides
Page Editor Recommended Practices for Developers
This guide is designed to help you build for the Page Editor and improve the user experience for editors. It is primarily aimed at back-end developers.