Build a great series of appropriate backlinks on your site. Have your keyword phrases be in the titles of said links. Make sure that these network links are related to your content, otherwise they could possibly work against you. Using backlinks is a great way to bring in traffic from various areas.
When publishing articles to other websites, post them to your own website first. Leave it up for a few days to ensure that the search engines index it, and then post it elsewhere. This will indicate to the spiders that your site is the originator of the content, and that the other sites are just reposting it, giving you the most link credit.
Create a page of content for each keyword you wish to optimize for a search engine. Do not try to smother your website with every possible keyword. Search engines are looking for relevant, organized content. If your page clearly discusses one specific keyword, it is much more likely to be used as a top result for that keyword search.