Those SEO techniques that needs to be avoided

I am going today to provide you people a few SEO techniques that needs to avoided. In fact the Google Blogoscoped blog has an interesting article covering the basics of search engine optimization. There are some basic guidelines for making your blog more search engine friendly, with tips about writing original stuff, making the posts accessible and spreading the word about your site.
The most useful part, however, is the final checklist on SEO techniques that should be avoided, check it out:

1. Don’t stuff too many keywords into places where they don’t belong
2. Don’t optimize for search engines at the cost of human visitors; if someone told you adding a dash to the domain name helps your rankings, but you feel that dash might confuse your customers, then don’t add it
3. Don’t trust people who promise you “instant #1 ranking”, “guaranteed top 10 positions” or anything of the sort
4. Don’t link to others from your site just because they promised a link back to you
5. Don’t link to others just because they paid you, unless you know exactly what you’re doing (i.e. you know about “bad neighborhoods” the “nofollow” attribute, PageRank, JavaScript-ads vs text links, what it means to get googleaxed and so on)
6. Don’t create multiple pages with exactly the same content
7. Don’t “litter” your URL on other people’s sites (and don’t let others people “litter” URLs on your site; if you have a web forum, keep it spam-free)
8. Don’t invest in a cheap server that won’t be able to cope with your traffic; don’t build your whole site on free website tools only – if you want to have a high-quality site & server, you need to pay for it
9. Don’t worry about a page’s meta descriptions, meta keywords and such; your time is better spent creating content
10. Don’t use tools that automatically submit your site’s URL to directories, search engines and such
11. Don’t present different content to search engines than you present to users; for example, don’t hide your text to visitors and show it to search engines
12. Don’t “over-optimize”; relax, if search engines required webmasters to heavily optimize, they’d be doing a very bad job
13. In general, don’t try to outsmart search engines (unless perhaps you intend to dedicate your life to that task); those maintaining search engines are paid to outsmart webmaster tricks, so in the long run, chances for successful tricks are low