Testing means checking the final product for imperfections (so that the imperfections can be corrected).  Testing is a standard practice across various businesses (the serious businesses) and helps in ensuring that the final product is of high quality. The only difference (across businesses) is in terms of the actual process of testing and the product that is being tested.  

Testing is an important tool for all website owners too. For website owners, the first thing to test is the overall look and feel of the website. Here you are look for overlapping texts, alignment of various website controls and text, the spacing between the website controls and consistency of design (including colors, fonts etc). Some people would not bother to even look into the content of the website if the overall look and feel was not pleasing. Remember, for most services/products there are sufficient number of vendors available and since a lot of people are short of time, they wouldn’t bother to read the website content if the website gave an unprofessional look in the first instance.  

The second important thing to test here is the spelling/grammatical mistakes and the general flow of the website content. Once a visitor to your website decides to go ahead and read the content on your website. He/She is expecting to know the benefits that you can bring to him, the cost of your services/ products and many other things about your services/ products. Some people are extremely fastidious about spelling and grammar mistakes. A number of people are actually put off when they read incorrect grammar or encounter a spelling mistake in a document or an email or a website. This is something that you can easily avoid through a round of thorough testing. Also ensure that you get your website content reviewed for flow and brevity (most people would be looking for brevity and clarity) by at least 2 people.  

You also need to test the response of your website to traffic e.g. how quickly your website loads up when the traffic to your website is at a certain level. This is also dependent on the web hosting package that you have gone for. However, you still need to test this out in order to check if the promise of your web host is a true one or not. You also need to ensure that the use of graphics and video/audio is limited so that the website loads up quickly even for the users who have a slow internet connection. 

So, these are some of the basic things that you need to test out and you can add more to the list based on your requirement.