To view your own website impartially enough to decide whether it serves visitors' needs, or conduct a critique that provides input for a redesign project, you need two things: a logical eye for what the site does and a reasoned analysis of how it can improve. Avoid criticism that relies solely on what you like, rather than what a site accomplishes or doesn't do well. Organize your impressions logically to offer useful input on site functionality.
First impressions can determine whether a site visitor stays long enough to view more than the homepage. If you land on a website and can't tell what it accomplishes, identify its audience and figure out who owns it. Then decipher -- or find -- its navigation system; Did its designers put form far enough above function to create confusion? Vincent Flanders, developer and curator of Web Pages That Suck, coined the term "mystery meat navigation" to denote any menu-and-link system that tries so hard to be clever that it becomes a test, instead of offering assistance. Among the many things you don't want a website to do, getting in the way of visitors' ability to absorb critical messages and information ranks at the top of the list of sins.
Once you record your observations of site accessibility, move on to an appraisal of aesthetic criteria. Focus not on whether you like the look but on whether it showcases the subject matter, provides an easy-to-read experience and abides by solid design principles. Look for hard-on-the-eyes combinations of colors, including light type on light backgrounds, and note the use of pages that reverse out, or place a dark background behind light type. Appraise the connection between the site's appearance and its overall branding, as well as how cohesively the design and color scheme suit the type of entity that owns the website.
A site that fragments content among many sub-pages to increase page views, or that neglects to apply navigation schemes consistently among pages and sections, adds difficulty to visitors' experience, either in an attempt to keep people from leaving or as proof that the site grew without proper planning. Test your ability to find something you know should be present -- a Contact page, an About Us page, a profile of the company or individual that owns the site -- and note how straightforward or convoluted the process becomes. Itemize the sections of the site and analyze how they organize its material. Looking at these items impartially becomes more difficult when you examine your own site, of course, but your critique stands or falls on your ability to think like a visitor.
Even simple-looking websites can rely on large volumes of scripting, CSS code and other behind-the-scenes underpinnings. Some of that code cuts corners to make design ideas work without finding the best ways to program a site. Some of it slows down page loading times. Worse yet, some of it violates the basic principles of HTML and CSS. As you review a site, look for problems with the way it provides its interactive experience: menu items that don't work, links that place offsite page content into onsite pages, code that triggers error messages in your browser. For an enlightening look at compliance, plug the address of a page into the validation routines at W3Schools.com (see Resources) and look for failures to comply with code standards.
One of the ultimate tests of a website's value lies in the content it presents. A beautiful, easy-to-navigate site with typographical and grammatical errors in its text should score as low as an ugly, crowded site with brilliant prose and beautiful images. Web designers can get caught up in the gestalt, or overview, of their sites without reading and reviewing what they say and show. Of course, if you design a site for someone else and the site owner provides its content, you may have limited control over what it actually says, both verbally and visually. Nonetheless, the look of a site can't outweigh the messages it conveys. Without real substance, a site becomes an empty shell.