A press release (PR) is one one the many tools available to you to draw more visitors to your web site.
Granted, it is not a direct method since when someone comes across your press release and clicks on it she is taken not to your own web site but to the PR site where the release is listed. However since the release also has your links and web address, the interested reader can still find and visit your web site.
With enough interesting press releases on the web containing your keywords, you can rest assured that surfers will eventually hit your release within the first page of search results.
Basic steps of writing a press release are:
1) Write a snappy header that includes your keyword(s). The closer to the beginning of the header the keywords are,
2) Optional: you can follow this with a Subheader which is again stuffed with keywords.
3) Next comes the "For More Information" block. Here provide the names, address, phone, web site address, e-mail address, etc. of the person that you want your readers to contact in case they'd like to learn more about you, your company, or your message.
4) Start your release with a date line, which is basically the City from which the release is issued, and the date.
5) Follow the date line immediately with the body of your PR. The first sentence and the first paragraph of the PR are the most important since they must include your keyword(s) to turn up in Google searches.
6) Including all the interesting facts and quotes and make it short. Usually 3 or 4 paragraphs is enough for a press release. Do not write a novel :-) People are busy and have no patience for long winding PR pieces.
7) Finish it again with the "For More Information" block. It never hurts to make sure people know exactly where to go to to see your web site. Or you can switch this with an "ABOUT XYZ COMPANY" block as well. It makes sense to end your press release with some general background information on the company (or person, or product) about which you have penned your release.