Beware… bad web design can happen to good web pages. Compelling design is an imperative aspect to your website. Your visitors will spend an average of .05 seconds before they form an opinion of your site once your page loads. Make sure your design aids the user experience to ensure they stay on your site.
Sliders
I know what you’re thinking, “how did this make it on the list?” The truth is, sliders aren’t working for you; they’re actually working against you. As a marketing company, you want to direct your viewer’s attention to how you can solve their pain points. Don’t give them a chance to lose track of this by distracting them with multiple images.
Pop-ups
Pop ups that offer you the option to subscribe to a blog, or engage in another action on your website, aren’t a bad practice, so long as they don’t hijack the user experience and subvert marketing efforts. A message that pops up after an appropriate time with an option for you to easily opt out of the box is effective. When pop-ups become mean - now that’s a problem.
Auto-play Videos
No one wants to be ambushed by sound and video. The goal is to get viewers to stay on your page, not drive them away. In an effort to get away from the noise, in many cases, your visitor will just leave your site. Respect your viewers and give them the ability to opt-in to watching your video.
Separate Mobile Sites
What Google says goes. If you feature a responsive, smart design, Google will give you a better rank and prefer your website over another that doesn’t use responsive design. A “mobile only” version of your site doesn’t give you a high quality user experience like having a responsive site does. Also, Google doesn’t recommend them; you’ll actually get penalised due to the duplicate content issue.
Many people who visit websites on a mobile device expect to see similar functionality to the desktop website. Mobile-only versions of websites tend to differ widely from the desktop counterpart, and thus only confuse the user.
Skeuomorphism
Skeuomorphism: this trend had a long life span, and I’m happy to say that it’s finally on it’s way out. It’s the design principle that makes digital images look lifelike-- and it's been used far too much.