The simplest KW research tool is google. Type in your topic and scroll to the bottom to see what related results show up. Use those to either write an article or to supplement other articles with some of the keywords. Yes, they are primary phrases so you may not rank for them right away but building your site with these in it will help get rank for them eventually. Also look at what other articles that show up for the keyword use.

And so on and so on. The point of this step isn't to come up with your final list of keyword phrases -- you just want to end up with a brain dump of phrases you think potential customers might use to search for content related to that particular topic bucket. We'll narrow the lists down later in the process so you don't have something too unwieldy.
Keyword Researcher is an easy-to-use Keyword Discover Tool. Once activated, it emulates a human using Google Autocomplete, and repeatedly types thousands of queries into Google. Each time a partial phrase is entered, Google tries to predict what it thinks the whole phrase might be. We simply save this prediction. And, as it turns out, when you do this for every letter of the alphabet (A-Z), then you’re left with hundreds of great Long Tail keyword phrases.

Hey Alex – this is a good question. No tool is going to be spot on. My advice is to not look too much into the accuracy of the metrics, but look at it more as a relative measure. I’m finding Ahrefs to be a good barometer for keyword competitiveness, but I’ve also heard great things about KW Finder lately. I think it’ll more come to personal preference. Both are solid options.

Given you have a good idea of where to start and are fairly confident you are speaking the same language as your client, jump start research by generating related keyphrases and long tail variants with the ever so easy to use Google Autocomplete. This tool makes predictions based on what you are typing that are a reflection of Google search activity. 

I want to share how and why I sold the company in order to both educate and inspire potential software entrepreneurs.  I certainly don't know everything and obviously companies sell for much more than I sold Long Tail Pro for (I won't be featured in Tech Crunch anytime soon); however, I'm willing to share what I have learned and hopefully that can be beneficial to a few of you.