There are two components or basic elements when it comes to appraising your domain/website. First, there are technical data specific to your website such as the domain age, the number pages the site has, the code the site was built with, the colors shown on the site and many other factors.
Second, there is the appraisal of the asset itself, which is to combine all factors and determine how much the domain or website is worth. This, of course, doesn ot mean that you wil get that price, if you decide to sell the domain or website. As with the sale of a property, the price can be higher or lower as appraised.