Checklist

General

• 404
• Favicon - https://realfavicongenerator.net/
• CSS no-js
• CSS print

Testing

• http://yellowlab.tools/
• https://www.dareboost.com/fr/dashboard
• https://developers.google.com/web/tools/lighthouse/

Checking on other browsers and devices

• IE11
• Edge
• Firefox
• Safari
• Smartphone (Android + iOS)
• Tablet (Android + iOS)

Perfs

• .htaccess - https://github.com/phanan/htaccess
• CSS + JS minification
• Remove Source Maps

Testing

• https://gtmetrix.com/

SEO

• robots.txt
• sitemap
• rel='nofollow' on links that shouldn't be followed by robots (like share links)

Accessibility

• keyboard navigation + focus styles
• label for each input
• title on links
• alt on imgs

WordPress

• configure Yoast SEO
• configure EWWW Image Optimizer
• configure WP Rocket (then check the .htaccess to add eventually missing good practices)
• configure SecuPress
• pass debug var to false