Add a Favicon to your site:

To be more easily recognized;

Display your brand as a sign of trust;

Differentiate your website from your competitors; and

It looks polished and professional which builds trust and credibility. 

Keep in mind that a Favicon has to be no larger than 16x16 icons like the image below so if you already have a design in mind make sure it is extremely minimal in detail so it will be easily recognized.  Below is the size of a 16x16 image: