I ask myself that question about once a month. My website looks fine to me, but what are other people seeing? And what are
Search Engines seeing? Here's a checklist of 10 ways to keep your website at peak performance: 1. Browser Compatibility
The first thing is to look at your website through other people's browsers. I do this regularly and I've sometimes been shocked at what I saw!
ANYBROWSER http://www.anybrowser.com
2. Broken Links
About 5% of all links on Internet are broken. A site that contains broken links gives a bad impression to visitors and is a frequent cause of lost sales. Also, major Search Engines and Directories will not list your page if it contains any broken links or missing images.
Here are some free link validators:
LINK SCAN http://www.elsop.com/linkscan/quickcheck.html
NET MECHANIC http://www.netmechanic.com/maintain.htm
WEBSITE GARAGE DEADLINK CHECK http://websitegarage.netscape.com/O=wsg uneup_plus/index.html
3. Web Safe Colors
Are colors on your web site displaying properly on other people's browsers? You may have a beautiful shade of lilac on your index page but it could look very strange on someone else's computer.
There are only 216 colors that you can safely use on Web. These colors display solid and consistent on any computer monitor or web browser that is able to display at least 8-bit color.
The Web Safe Palette contains six groups of colors with 36 colors per group. These 216 web safe colors can have any combination of following RGB (Red Green Blue) values: 0, 51, 102, 153, 204, 255 (each RGB value must be divisible by 51).
Here's a good palette of web safe colors:
WEB-SOURCE SAFE COLORS http://www.web-source.net/216_color_chart.htm
4. ALT Tags
ALT Tags allow you to give an alternative to people who have 'view images' function turned off in their browser. Let's say navigation system on your website is a series of buttons that link to other pages on your site. If you don't have ALT Tags, people who have 'view images' function turned off will be unable to navigate through your site - in place of your button they will just see an empty space.
But an ALT Tag allows you to tell those people what that button does. For example, if button is a link to your 'Site Map' you could insert following ALT Tag: 
ALT Tags also allow you to raise your keyword density. For every image that is not hyperlinked you could insert your main keywords. For example: 
5. Meta Tags
Meta Tags are so important they deserve a whole article on their own. The most important Meta Tags are Title Tag, Keywords Tag and Description Tag.
The Title Tag should be no more than 64 characters (longer than that and it will be cut off in some Search Engines).
The Keyword Tag should contain about 5 to 10 keywords that appear on your page. Never include words that do not appear on that page - in some Search Engines your website will be penalized for this. Do not repeat same keyword - this is called 'keyword stuffing' and is also frowned upon by Search Engines.
Separate your keywords with spaces (not commas). This allows Search Engines to combine your keywords into phrases, for people who do 'phrase searching'.
The Description Tag should be no more than 200 characters. Include as many of your keywords as you can. Remember also that your Description Tag must be enticing - it must make people want to visit your site.
