Don't forget to underline your links
We often try to make our websites unique and forget something basic, such as the fact that links should almost always be underlined because the percentage of users with some kind of vision problem is very high.
On the contrary, emphasizing things that are not links is a bad idea because people will tend to click on them.
Do some usability testing and you’ll quickly see that using an underline for anything other than a link on the web is problematic. Users will assume underlined content is a link and wonder why it’s broken when they press it and nothing happens. (source: tempertemper.net)
In short, I believe there are a lot of issues that we usually don't think about when we create a website.