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.
The reason I sometimes use this facility with the GKP is to find volume amounts for the keywords I’ve chosen. But, these days, it’s not so important. As long as the Long Tail Keyword makes sense and is something I would put into a search engine, then it’s good enough. Sometimes the most blazingly obvious keywords are often over looked by eager, trying-to-be-clever marketers. Sometimes you need a tool to highlight them.
1. Create a New Project. By clicking on the “+” icon located at the left upper corner, a new pane will show up allowing you to: enter your new project Title; choose your project’s Country (which affects the total of local monthly searches and top 10 Google results shown); pick your project’s Language (which affects generated keywords and the top 10 Google results for users that use that language); select your Search Network (which affects the number of reported searches depending on your choice between “Google” or “Google & search partners”); and toggle the Adult Ideas switch on or off.
If only it were that easy – right? I’ll be the first to admit – it’s not always that easy. I’ve created lots and lots of these types of sites over the past few years – and only a handful of them worked out. It can be a very hit or miss thing. But I do have one site in particular that I would like to highlight for you. It happens to be the very first niche website that I ever created! Why highlight this specific site? Because my very first attempt at a niche site happens to still earn more than enough money each month to pay for the expenses associated with Long Tail Pro! Check out the screenshot below from my Adsense account which shows stats for just this one site for exactly one year previous from the day that I am writing this post.
I would like to get LTP but I’ve read that people have some issues according to Keyword Planner and Moz. Do you still recommend this tool? How accurate is it’s data comparing to previous versions? Does Keyword difficulty still works as it should? Maybe it’s better to wait untill some stability of this software? I don’t want to waste money for some tool which doesn’t work properly.

* Please note our tool currently assumes Google having ~ 83% of the market, with Bing + Yahoo! splitting the remaining 17% of the market. Actual market conditions may vary significantly from that due to a variety of factors including: search location, search market demographics, how much marketshare mobile search has relative to desktop in that particular vertical, etc.

I was going to post screenshots here showing my numbers for the past year – but the dashboards in the old affiliate platforms (Clickbank and JVZoo) don’t provide the best visuals – so I’ll just show you my total affiliate income for the past year. In one year (March 13, 2015 to March 13, 2016) I earned $3867.60 in commissions for promoting Long Tail Pro. Not bad for having just a mildly popular ‘passive income blog’ and only a small email list!
Long Tail Pro is a keyword research tool that helps you quickly find low competition keywords for your website.  In particular, the tool is built for people doing SEO (search engine optimization) as opposed to people doing paid ads (Google Adwords PPC).  I'm sure there are some advertisers that use the tool for paid ad keyword research, but the tool was built for SEO keyword research.