iOS does not support Flash. If you want your site to work on mobile devices, replace Flash with HTML5 or at least include an HTML5 fallback to support that ever-growing group of users.
It’s true that the average web site’s size has surpassed 1MB. But it is also true that most web sites are excruciatingly slow and unusable on mobile — mobile being the future of web browsing.
Be among the best. Keep your pages smaller than 500K.
If a class name you have selected is very similar to an HTML element name, this often indicates that your HTML can be more semantic. Use <footer>I am a footer</footer> instead of <div class=”footer”>I am a footer</div>.
Code such as <h1 class=”largeHeading”>Title</h1> is redundant since h1 means “largeHeading.” A preferable class name would be more specific and indicate how the heading is used. For example, <h1 class=”masthead”>Title</h1>, would indicate both how and where the class is used.
Missing the alt attribute for an image may seem like a small thing, but it is important for accessibility and it is required.
Images make pages slow; by using them you are adding http requests and files that need to be downloaded. The only time I would suggest it is for logos, which technically are text but not the type of text I’m talking about. Menus should definitely not be graphics.
Google Analytics or some other web analytics software should be included and used. The priority of this item depends on the type of site, but it is essential for most.