1. Clean, semantic markup
The best thing you can do to lay a solid foundation for a usable mobile website is to incorporate clean and semantic markup. What you may be able to get away with on a traditional website may cause significant problems on a mobile website. Clean markup will help ensure that the browser is capable of properly displaying the website, and it will help give visitors a pleasant experience, with no unnecessary difficulties.
2. Separation of content and presentation with CSS
Alongside clean, semantic markup is the need for the separation of content and presentation. Mobile visitors are much more likely than desktop visitors to see a website with images and CSS disabled. The most important thing for these visitors is to be able to access the content and links: presentation is secondary. A website that uses clean, valid markup, with CSS to separate the presentation from the content, is off to a great start as a mobile website.
3. Alt tags
Because it’s likely that some visitors will not be able to see images on the website (or will choose to disable them), alt tags are extremely important for usability purposes. Of course, alt tags should be used anyway, but it’s even more critical for mobile visitors.
4. Labeling form fields
Like alt tags, form field labels help make a website much more usable for mobile visitors. Imagine trying to use a form without knowing what is supposed to go where. Simple details like alt tags and form field labels can make a big difference this way.
5. Use of headings
With inconsistent and often limited styling of text on mobile browsers, headings become more significant. Mobile browsers are less likely to style text exactly how you would like it to be, but h1, h2, h3 and other such tags generally help make certain text stand out and build the structure of the page from a visitor’s perspective.
6. Avoid floats if possible
Even if a mobile browser correctly displays a website that uses floats for layout, it’s unlikely the website will look good on a small screen. Usually the website will be more usable and look less awkward without floats altogether and with content simply stacked up.
7. Reduce margins and padding
Most likely, your mobile website should have smaller margins and padding than your main website has for traditional visitors. Of course, this depends partly on how much of a margin and padding your website currently has, but very large amounts can make the layout awkward.
8. Pay attention to navigation
Most websites have a primary navigation menu very high on the page. This is helpful on mobile websites as well, but generally, mobile navigation options are scaled down. Provide only the most relevant links, and, if possible, give visitors an easy way to access the other navigation items.
9. Consider Color Contrast
Because mobile screens may not have the same appearance as desktop or laptop monitors, make sure the background and text colors provide adequate contrast so that the content can be read easily.