Hi Daniel,
I notice that you ask about Keyword software. My experience with the Internet is that some people think that if the spend money for something it is better. Everything on the net can be perform for free if you take the time and dig deeper.
However, that is the big question. Time and Money!
I use a couple of different method, "Web CEO" is one of my favorite here is the link:
http://www.webceo.com/ There is a free version that you can download. For Internet Marketing this one is just fine. (Not an affiliate link)
Also, here is a link for a movie that you can watch on How to use LSI to build your keywords.
http://www.nicherockets.com/lessons/lsi/
If you have any questions just PM me?
Best,
Jimmy.