This is the exact opposite of mistake #1. Let me start by revealing a dirty little secret when it comes to website design. Most people think, Oh, I’m going to hire a professional website firm because I want a “real website” As opposed to a Word Press website or something else. And what most people don't realize is that all websites are made from the same stuff.
Decided by the US Supreme Court in 2002, this case  held that even requests for accommodation that might seem reasonable on their face, e.g., a transfer to a different position, can be rendered unreasonable because it would require a violation of the company's seniority system. While the court held that, in general, a violation of a seniority system renders an otherwise reasonable accommodation unreasonable, a plaintiff can present evidence that, despite the seniority system, the accommodation is reasonable in the specific case at hand, e.g., the plaintiff could offer evidence that the seniority system is so often disregarded that another exception wouldn't make a difference.
This title outlines the administrative processes to be followed, including requirements for self-evaluation and planning; requirements for making reasonable modifications to policies, practices, and procedures where necessary to avoid discrimination; architectural barriers to be identified; and the need for effective communication with people with hearing, vision and speech disabilities. This title is regulated and enforced by the U.S. Department of Justice.
Distinguishable: To assist color-blind users and those with other visual impairments, color is never used as the sole means of conveying information or prompting the user. Audio lasting more than 3 seconds can be paused, or the volume can be controlled independently of the system volume. Regular text has a contrast ratio of at least 4.5:1, and large text has a contrast ratio of at least 3:1. In addition, text can be resized up to 200 percent without causing issues with the website.
What do you want your website to look like? Consider websites that are similar to the one you’d like to build, ideally in the same industry or serving similar types of customers. Build a set of examples of types of pages, design aspects, and website features that you can hand off to the web designer — the person you hire should have experience creating websites with the features you want. If they don’t have the right skill set, they’re not the right pro for you.