Everyone wants their websites to be search engine optimized, or SEO-friendly. However, there are some common errors that people make when they're doing SEO work on their site, and these errors can actually cost them that highly coveted top ten ranking that everyone wants. Here are some things to avoid when doing SEO work on your website.

Remember the ALT tags! Almost every image on your website (not including the background and any images that serve as buttons and the like) needs to have ALT text. This is the text that shows up if the image doesn't load. More importantly, however, it's the text that tells search engines what the image is since the programs can't actually see the picture. A good ALT tag will include two or three of your keywords, and it's a great place to stick in extra keywords that the viewer will (hopefully, unless your image is missing) never see.

Don't use the same title tag on every page of your site. While it may be easy to simply write one title for your homepage and then leave it on every page, this is another place where you're losing out on a place to stick keywords. Vary the title for each page so that search engines will notice the difference, and try to include different keywords for different pages.

Avoid scripts! While Flash and the like are becoming more compatible with search engines, it's still difficult for more search engines to see inside Flash objects. This means you're losing places to put meta tags, ALT tags, and more.

Don't just write for robots. While writing articles with a high keyword density might get your page ranked higher by the search engine, it's going to send actual human readers away. They don't want to read anything redundant or clumsy. “Our furniture store in London provides great furniture for London residents looking for furniture designed specifically for London” is going to either annoy readers or make them laugh at the horrible writing. Be sure your SEO phrases and such can be integrated into the text seamlessly so they don't stand out and don't over-use them.

Also, actually write your website text yourself (or hire someone to write it). Don't plagiarize - don't copy and paste text off of one website and put it on yours without making it clear where the text came from. Too much duplicate text on your page will be flagged by search engines.

Likewise, avoid any bad SEO practices like hidden text or keyword stuffing. Hidden text refers to adding a ton of keywords at the bottom of a website and then making them the same color as the background, effectively hiding them from viewers. Search engines still see them, however. In the past, this was a technique that did actually make search engines rank sites higher, but today's robots are smart enough to recognize this technique and ignore it. Likewise, keyword stuffing, or making a webpage that's almost nothing but keywords, raises a number of flags in search engine robots and may actually get your pages ranked lower.

Finally, make certain all of your links describe where they're going. No one likes to click links that aren't clearly described by the surrounding text or give a good idea of their target. Plus, links are another factor a search engine uses to determine site relevancy, so not clearly marking them is detrimental in several ways.