An appealing design for your Web site
Your website design is the first impression you make on your customers and visitors. There are a few sites which are enriched with good contents but are poorly designed but foresee a fact that many other sites may come out with beautiful designs as well as the same enriched contents. So imagine the future feed back of the site visitors. Your content may be too great, but take care not to make a poor design. Think how much repeat traffic and referred traffic you will get if you have both great content and great design. 
Design: It is a matter of taste and target of audience to some degree. So design taste varies. What looks good to one visitor may not be so great to another. Remember the old adage, "one man's trash is another man's treasure". Creating a distinctive visual style and applying it consistently is the best way to bind a series of subjects and web pages together. 
Layouts: The layout of your site is important on design element. A webpage is a document and it is plain and simple. It is like formatting a letter, an outline, a report, or an advertisement. Establish a layout grid and a style for handling your text and graphics, then stick with it to build a consistent rhythm and uniformity across all the pages of your site. Make it easy to follow, pleasing to the eyes. Learn to use tables and nested tables, lists and even well designed frames for controlling layouts. 
Color: It has a lot to do with target audience as well. What appeals to a teenager may not work with the audience of baby-boomers, and so forth. But anybody can appreciate color coordination. Color coordination can be learned. Yes, it's easier if you have a natural "knack" for these things, but you can learn basic color coordination techniques that make the difference between "tacky, Yuk!!!" and "soothing to the eyes". 
Safe Colors: Everybody does not have 16 million colors on their computers. So it is better to use the 216 web safe colors. Please notice that it is 216 colors, not the 256 colors that are more usable. The appreciation of your site depends on the video card capability and at the mercy of the viewer's personal computer system. It is better for you to stick to 6 x 6 x 6 bit color resolution (216 colors) to cover the majority of Internet users. The 216 color palette gives you plenty for design options not the 256 colors or 16 million, but still plenty to accomplish with what you want or need to do with color. 
Page Load Time: I may use long loading pages in my personal site for demonstrating several techniques or chatting with friends and other developers, but I must never use it for professional site design (unless my client insists). This doesn't mean you have to give up everything on professional sites but take it easy and use only one high-load-time element or two. Learn to compress your graphics properly, if you've got that much "stuff" then break it up into more than one page. 
Don't Overdo: A typical mistake among developers is to overdo when putting together a website. Try to use extras in moderation. Some common things that get overused are: 
graphics 
background images 
bevels and other graphic tricks 
excessive frames 
text scrolling, animated .gif's, page fade-ins 
Too much of something just comes off as being "cutsie", tacky, or unoriginal...but it can add the right touch when it is used properly. Use things that compliment your site's content, and don't overdo it with extra techniques and tricks. 
Readability:  Make your pages as easy to read as possible. Black text on a white or off-white background is the easiest to read. There are plenty of hard-to-read pages that use backgrounds as the same shade as the text (dark text on a dark background and light on light), or the "neon" look with bright color text on bright color background. 
Use the easy font: Give your readers a font that's easy on the eye.  Use a sans-serif font - arial or verdana. They are good choices. Put "sans-serif" generic font in your last html tag attribute to cover anyone that may not have a specific font you listed as a first choice or second choice. 
Browser and Monitor Compatibility: Learn to make your web pages compatible with both Microsoft Internet Explorer (IE) and Netscape Navigator. Test the site after preparing it, in both browsers and on different screen sizes or resolutions. 80% of Internet users are on the IE browser, 80% using 800 x 600 resolution, and most on a 15" or 17" screen....but you cannot afford your site look poor to 20% of the market. Make your site compatible with both browsers and take that silly "best viewed with..." graphic off the site! Furthermore, use alt tags in your graphics for people who surf with images turned off or on smaller browsers which don't support them. 
Using Java:  Many people turn the Java off for one or another reason. Or they may be using a browser that doesn't support Java. Therefore, if you use a java driven menu (quite popular nowadays), better have some alternate navigation too.