There are several things you can do to make sure a website is effective in offering viewers a delightful experience. Below is just a few of the most important.

You want to make sure that the color scheme of your website works. For example if your background color is blue, and your text is red, visitors to your site, might find this a bit hard to read. Make sure their is just enough contrast in the colors to offer a pleasant look, while still being easy to read.
One of the most important elements of a website is the header. The header is usually the topmost part of the website, and contains your logo, and and sometimes an attractive image that represents your website. The header is usually the first thing a visitor will see on your website, and you need to make sure it gets their attention without causing to much of a distraction. Your header alone could determine whether someone continues on your website, or leaves it to find something else.
Your site navigation is very important to your visitors ability to browse your site. If you visitors have a hard time navigating your site, they could be missing important information that you are offering. It is usually best to have a navigation menu at the top, in a tab or button style. It is also good to have a bread crumb style menu present as visitors are navigation your site. The breadcrumb menu that shows the visitor the path they have taken to arrive at the current page, and gives them easy access to return to a previous page.
SEO is Search Engine Optimization. This is the process of optimizing your website so that search engines can easily find it. If you do not know how to do this, and most dont, their are plenty of companies offering this service. Be cautious with anyone stating they can guarantee you a number 1 spot. Everyone wants to be number 1, and obviously it is not possible for everyone to be at the top.