A mobile, a tablet with ok sign and a desktop in middle with a tick mark.

User Experience

What people feel matters most. More than UI.

User Experience

Impact of UX on SEO.

These are not web design guidelines, rather 2 specific user experience points, that have influence over search engine optimization. When you design your site keep these in mind.

Speed is an important factor in ranking and there are PageSpeed rules used for faster loading webpages. Here is a resource article on Webpage Speed
Next point is mobile experience as Google is using it as ranking factor. So, it is an important factor and we are going to discuss it as following.

Mobile User Experience Overview

It is an important factor because your visitors are using devices of various size. And their experience with your website matters to search engines. 3 available methods: You may change the user agent in your server or use a different url for mobile browsers. But most useful method from seo perspective is to use a responsive web design (wiki article on it). here is a vast resource is available for mobile seo and a tool to check if your page is mobile or not.

Mobile Design

4 major factors for perfecting mobile specific seo.

Media queries
Essential css code parts for mobile design. See technical details here
Enlarged tap size
Places in a touchscreen, user taps with finger should be large enough. So that user dones't tap some other link.
Don't block Resources
If you do, google will not understand your ux. So don't use robots.txt to block js and css files.
Smartphone mobile device with camera, with vibrant tiled display. Background with source code in red page.
Size content to viewport
Use this google recomended viewport meta tag and you are done.
Use legible font sizes
Using fixed font sizes will make your content less readable. Fonts should also be responsive with device width.
Stop frontend plugins
Like flash, java, quicktime etc. They commonly cause trouble to mobile browsers and people will avaoid such sites.
With 1000+ active installs, an useful plugin for on-page seo insight