Keyword research for a business blog - first try

This is my first foray into learning more about search engine optimization.  I did some research to see which keywords might be most appropriate to get this blog seen more by people looking to improve their business blogs.  I used the keyword tool on Google Ad Words to look at the most popular searches and related searches.  I know there are more sophisticated ways to go about this, like buzz pocket mining (ugh - who made up that phrase?) but I am taking baby steps here.

So, the title of my blog is "Corporate Blog Writer."  But very few people (relatively) search for the phrase "corporate blog" per month -- only 9,900.  Maybe they're a very targeted 9,900.  Just the people I want.  Maybe not.  Who knows at this point.

What is interesting is that the next, related search has nearly twenty-five times that number of searches: more than 246,000 people search the term "business blog" per month.

Other top searches:

• Search engine optimization: 9,140,000
• SEO: 7,480,000
• Keyword: 5,000,000

And much smaller searches that might be more appropriate to what I'm doing:

• Freelance writer: 135,000 (and look how high this lady turns up!! Nice job!)
• Copywriter: 135,000
• Online writing: 135,000
• Blog content: 110,000

I know that I shouldn't spam my own content with these keywords, I am definitely going to throw in "business blog" more often.  

Any other hints for keyword research? Also: good site analyzers to evaluate your own keywords as they are now?