There is no benchmark on a relevant standard on how a website should have to perform its duties to attract visitors. The differences between "good" or "bad" is always about perceptions, making a good design may not appeal to all the crowd. But there are several components that how a website should have to make it perform at its peak without leaving any essential information.
There are several things you should know when you hire someone or a company to design a website. You should ask your potential designer the right questions and feel confident that you are hiring the right person to build or re-configure your website.
Animation
Content-animated flash websites are really good to see and very interactive. There is nothing better for the eyes that great eyecatching designs. Unfortunately, search engines like Google or Yahoo! cannot see any of it. It is that web crawlers cannot read the movement or action at all. Though this too is already a good reason not to have them, flash designs also decrease overall performance of your website. This will take too long to load for the search engine’s crawler and eventually they will leave and your website will not be crawled for a period of time because of their algorithm.
Web Optimized
Statistics show that users will wait only 4 seconds to begin to see a page loading when they first visit a website; and only 20 seconds for the entire page to have downloaded in the screen. Any longer than that and they will hit the back button in the browser and leave, probably for good. Make sure your web designer knows about this and thus will balance your site with light weight graphics and text.
User Friendly
Research shows that users do not read websites, they skim them. Your visitors will look around feverishly for anything that is interesting or resembles what they’re looking for. A good web designers know this. They places important information strategically throughout the website, makes good use of conventions (i.e. anything clickable should be underlined), designs a user-friendly website with intuitive navigation. This is designing with usability in mind.
Too much of something is never good. So as advertisements. Too many ads or pictures or irrelevant content that lead to other topics is not good for your website image or income revenue.
Search Engine Optimization
Besides the issue of search engine visibility, good web design incorporates competitive and relevant keywords within the text of the page, and ‘behind the scenes’, tucked away in what’s called the HTML Meta Tags, which are not usually visible to human eyes. The research and placement of the keywords are extremely important if you want your website to stand a chance before the search engines, and therefore, have your website make a positive impact in your business. There are many other ways for search engine optimization but what it really do is attracting crawlers to the site and make them 'confortable' so they will keep returning and place the site above your competitors.
Tableless CSS Markup
Web designers have traditionally relied heavily (or even exclusively) on the use of HTML tables to display their web designs on the Internet. However, tables present multiple issues on flexibility, interoperability, and most importantly accessibility. Tableless CSS markup has now become the standard in the web community, specially since it allows to separate content from the presentation (or design) of a website with enhanced control and flexibility; it demands less bandwidth usage; and it fully supports mobile and hand held devices. Since HTML table-based coding will sooner or later be phased out, it behooves you to check if your web designer will use the highly recommended tableless CSS markup when building your website.
Browser Compatibility
Since the Internet has continued to grow at an exponential rate, so have the Internet Browser brands. While the well-known Internet Explorer decrease its popularity, Firefox and Chrome are battling to be number 1, there are well over a dozen different options out there that are being used by internet visitors. Each of these browsers decodes the HTML, XHTML or CSS of your web site in slightly a different way. Sometimes the design will hardly be affected, yet other times the interpretation given to a particular piece of such code can drastically alter the overall design or composition of your site. Make sure your website will be compatible in at least the 3 most common browsers: Mozilla Firefox, Google Chrome and Windows Internet Explorer.
Today, as more and more people are using their mobile phones and tablets to be on the internet, website designs should also be compatible with mobile browsers.