You can spend a lot of money figuring this stuff out. Pay for keywords, pay for keyphrases, things like that.
Here's something that is free: think about your vocabulary as you write.
Remember that your reader will have to surf to reach your content, unless you're so popular with them that your site is already stored on their machine somehow (bookmarked, RSS feed, etc.).
1. Write for that surfer. Use "drunk driving" not "driving under the influence." Try "Univ." or "U." instead of University; car instead of auto; miles instead of distance.
2. Watch yourself as you surf. What are you asking from Google when you're surfing the web? Learn from your own searching ....
Writing for the web involves more than writing for print. Maybe there will be a day when search engines are so powerful and all-encompassing that this won't be true any longer. But we're not there now, so Cowboy Up.