Things to Do

• The Title tag is a container for keywords that are relevant to related content for a given webpage. It is hidden from page view but used in search crawling and search indexing. Only the first 70 characters are looked at, so keep it concise and simple. Every Title tag should be carefully crafted to optimize this small space
• The Meta tag is a second hidden container in which relevant keywords can be placed. Only first 156 characters are indexed here.
• H1 tags are header level 1 tags (if they are part of the design). These are typically the primary headers in the content of a page. The header descriptions need to be crafted to utilize keywords in a way that creates a clean, thoughtful header to explain the content that follows it.
• Keywords should be used in the page's text-based body content at least twice. On pages more than 500 words in length, make sure that keyword density is at least 1.5% (but no more than 6 or 7%). Keyword usage should be evenly distributed throughout the page

Things to Avoid
The Meta Keyword tag is completely ignored by Google. As of 2010 it had nearly no weighting by Yahoo. In the early days of search engine optimization, the meta keyword container was indexed and heavily weighted. But because the container contents were frequently abused by those black hatting, or indexing the tags with keywords that did not match any content, the practice of using the keyword meta tag has been all but abandoned.
Google's List of Tags
The following link identifies what meta tags and meta data Google does or does not index. http://www.google.com/support/webmasters/bin/answer.py?answer=79812