Don't depend on "expert consultants" or your media agency to make all your decisions.  Learn the basics and apply them for yourself, so you have a foundation of knowledge to make the best decisions.

Keyword Research is not just about words.  Think of each word or phrase as its own niche market.  That market has viability, or not, and is a capsule of consumer behavior.

In the variety of classes I've taken, webinars I've attended and my own keyword reasearch for my Affiliate business, the following 8 Best Practices have worked for me.

8 Best Practices for Keyword Research

 1.  Using the "view page"source function of your mouse's right click to check competitive landing pages for keywords and keyword phrases in their meta tags.

2.  Using forensic tools like PPCWebSpy (free) the Cash Keywords toolbar for Firefox (free) or Google Cash Detective (not free).

3.  Using Alexa.com to search on competitor or related URLs.

4.  Always Google Keyword Tool.  But not just the Keyword search, also the search on URLs to view SiteMaps and site keyword categories.

5.  Researching Demographics using free tools:
adlab.msn.com
google.com/insights
quantcast.com

6.  Browsing Bookstores, Amazon.com, Barnes and Nobel, offline and online to find related keywords about the subject of product in order to create a list of similar product names.

7.  Making sure you have a solid Negative Keyword List.

8.  Digging beyond Broad keywords using a variety of tools such as:
synonyms.com
thesaurus.com
quantcast.com
wikipedia.com
quintura.com

I hope these will help you too!