To improve site rankings and increase understanding of the listing process, there are many tasks that can be done on a regular or semi-regular basis. Optimizing rankings within the search engines is also to help ensure that a site attracts the right traffic.
Some of the monthly and weekly promotion tasks are:

Crunching and examining log files

Data contained in log files is an excellent resource for identifying which engines are sending the majority of traffic to a site. It can also show which key words or gateway pages are generating the strongest traffic and what are those visitors doing when they enter the site.

Searching the Search Engines

Conduct a search of the search engines to analyze where the highest rankings of the site have materialized and what keywords are generating the best rankings. Different search engines use different rules to rank pages. Individual gateway pages should be created based on the knowledge and interpretation of what each search engine is using to determine top rankings. Several pages can be tested out on one or more engines and the pages that have the most success can be kept, while the unsuccessful pages can be dumped or revised to achieve a higher ranking.

Learning more about how the search engines work

Each search engine uses different rules to determine how well a Web page matches a particular query. As a result, building a single page that gets a good score in all the major engines is just about impossible. Learning how each engine ranks pages is also hard, since the engines often keep this information as a closely guarded secret. However, with a little patience, some experimentation and reverse engineering, the way that many of the search engines work can be discovered.

Resubmitting the site

For engines that reject a site or don’t list it high enough, it is strongly recommended that more information is learned about the engine’s criteria before resubmitting. This information should then be incorporated into gateway pages or key word revisions in order to have greater success with subsequent submissions. Fine tune the page (or pages) make adjustments to TITLE tags and META tags, then after resubmitting the site, track the results to further learn about the engine’s criteria and which adjustments made an impact on the rankings. Don’t be afraid to experiment, take some risks and gather data as you proceed.

Checking log files for traffic being directed to erroneous pages on the site

This is good news!! Don’t dump these pages or remove them from the search engine as most people will do when they redesign their site. Any page with a high ranking is of value. If a page is bringing traffic to a site, leave that page on the search engine, don’t change it but rather redirect the traffic to valid pages in the site.