During the last 10+ years I've tried to stay on top of all the latest trends in web design, but I realized the most important things never change: 1) Test brow

During the last 10+ years I've tried to stay on top of all the latest trends in web design, but I realized the most important things never change: 1) Test browser compatibility. 10 years ago that meant IE and Netscape. Today there are a a lot more browsers, but luckily there are standards now and the browsers mostly stick to them. But you have to test on desktop now, on mobile, and on tablets. 2) Test page load speed. While average broadband speeds have increased considerably in the last 10 years, there are still a lot of users stuck with slow lines. And when you're on mobile, you will have slow connections even if you live in a large city. If you have a Mac, use Network Link Conditioner to test how your website performs on slow or unreliable networks. 3) Progressive Enhancement. Don't rely on Javascript, Flash, Java, HTML5 video etc. Make sure your website is usable with everything turned off. If you want to use awesome animations and videos to present your content, make sure that you provide a simple textual description as an alternative. That's important for search engines, but also for users who can't view your interactive content for whatever reason (missing plugins, slow connection, e-ink display, no speakers connected, etc.)