While there are many strategies to use for Search Engine Optimisation, there are some things you shouldn't do. Your site can be penalized by the search engines for some of these. Or while you think a strategy is helping to raise your rankings, it may not.

TEXT IN GRAPHICS
Most search engines don't read pictures or graphics, so use as much text as possible and make sure it's relevant text. Good information and solid content that focuses on your product and services will allow the search engines to identify your site and give you a better positioning within those search results. Sites that use an image full of text, instead of text, can appear as an empty page to a search engine. This is specially relevant on a home page.

MOVING A PAGE THAT ALREADY HAS A PR
If you move a page, it will lose its PR until the next time Google indexes it. So set up the page's original URL to direct people to the new page, and tell them whether the move is permanent or temporary

DEAD ENDS
All page should have a way out or exit via a link.

ARTIFICIALLY INCREASE A PAGE'S KEYWORD DENSITY
Loading pages with irrelevant words in an attempt to increase a page's keyword density will penalise your site. This includes stuffing ALT tags that users are unlikely to view.

USING HIDDEN TEXT OR LINKS
You should use only text and links that are visible to users.

LINKS FROM LINK FARMS AND NON-RELEVANT SITES
Make sure they are from other relevant sites, not link farms or FFA sites. Best is links from pages without many other links, from sites whose content/theme is similar to or complementary to yours.

UNNATURAL LINKS
The search engines prefer your linking to be natural', to appear as if they were placed in the normal course of your business dealings. Not too many at a time, not all coming from link pages, not all reciprocal links, and not all coming from only PR 5 or above sites (looks like you bought them).

USING THE SAME TEXT IN INCOMING LINKS
It isn't natural to have every website that links to you have the same text on the link description. The natural tendency would be to have a certain percent be the site's name, but after that it should be a wide variety of description. Your link text description is a key factor for how your site/page will rank, so make sure that you keep that in mind as you specify your preferred link text description on your website.