Because someone who is looking for something that specific is probably a much more qualified searcher for your product or service (presuming you're in the blogging space) than someone looking for something really generic. And because long-tail keywords tend to be more specific, it's usually easier to tell what people who search for those keywords are really looking for. Someone searching for the head term "blogging," on the other hand, could be searching it for a whole host of reasons unrelated to your business.
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.
1. AdWords Keyword Planner - It's still the standard, although Google keeps making changes that just aren't helpful. I get that they want us to treat closely-related keywords in such a way that we're not creating multiple pages when we should just have one, but I'd appreciate it if they'd still break down the volume for each keyword that makes up a group (or at least list the keywords they're clumping together into a group).
Keyword Overview looks at the entered term on its own and addresses expected searches per month, the difficulty of competing against Page 1 results for the same term, a rough estimate of organic click-through opportunities (versus paid ads and non-organic positions on the search engine results page), and the perceived priority that the user should assign to optimization for this term, where the higher the score, the higher the demand and a lowered level of competition.
Finding the best keyword research tool also depends on your own experience with SEO subjects such as buying keywords, long tail content, long tail SEO and using low competition keywords. For instance, a newbie looking to use long tail marketing may find something like Long Tail Pro V3 a little too confusing and a bit expensive as it’s a monthly fee and has a confusing interface.