Link Building Tips
Also applies to directory submissions
The search engines (SEs) have evolved over the years and will continue to evolve in the years to come. Google is by far the furthest along the evolutionary path.

If your site is in a competitive search field then you really have no choice. Without a large number of links to your site, you have very little chance of achieving high search engine rankings.

The following are some suggestions on how to build effective SEO links while minimizing the risk of having your hand slapped by the search engines.

Link Building Tips
Vary your link title text
The search engines look for evidence of unnatural behavior. In a perfect world, the SEs would like to see all links gained naturally. Since it would be highly unlikely for a large number of individuals to link to your site using the same link text you should vary your own link text.

Vary your link descriptions
Google is likely getting better at analyzing the text surrounding a link. Again it would be unnatural to always have the exact same text. The same descriptions could also trip duplicate content filters.

Seek links from related sites
It is widely believed that a link from a website in the same field is much more valuable than an unrelated link (most applicable for Google and Yahoo). Perhaps too many unrelated links can even get you a penalty.

Mix homepage and internal links
You should have some of your links pointing to internal pages of your websites, rather than have all you links pointing to your home page. Again, naturally attained links will seldom all point to your homepage. Having links pointing to your internal pages will also help your SE results.

Seek links from authority sites.
Links from authority sites will provide much more weight than non-authority sites. We can only guess at what sites might be considered authorities. Google seems to favor .gov and .edu sites.

Seek links from older sites
Links from older, more established sites will provide more weight (applicable to Google)

Seek links on the upper half of the page
It is believed that the higher a link is on the page the more weight it will provide.

Seek links within page content
Links located within content will provide more weight than links in the margins or footers of a site.

Seek non-reciprocal links
Do reciprocal links provide less weight. I don't know if the proof is conclusive on this issue. If not, algos that handle this could be around the corner. It is feasible that sites with too many reciprocal links incur a penalty.