You actually don’t need much work to develop a website with high usability. Most web agencies work so hard on sophisticated design and feature, they often forgot about how user loves simplicity.

They could use some clear content with straightforward language. That would give them the whole important point of information as quickly as possible. Advanced and scientific words: avoid them. Use everyday words instead.

Also gives them some simple layout. Don’t overload your pages with too many function and information. Keep ‘em nice and clean.

Provide good navigation. Main navigation must be accessible at all time. Not only that, always gives user information about where they are within the website.

And also hyperlinks. Make them clear and meaningful. Give them some relevant hyperlink title. And of course relevant page to jump to.