Keyword research tools are used to identify popular words and phrases people enter into search engines and to figure out what to rank for. Keyword research gives marketers an idea of how high the demand for a keyword is and how much competition the terms in the organic search results has.
There are many different websites which offer all types of seo keyword research tools. A free keyword tool is keywordtool.io where you can only search for keywords without data. Another one is Jaaxy a more affordable price starting at 49$ per month it provides Unlimited Searches and manual QSR (shows the number of Competitors). A high-end keyword research tool is Semrush starting at 99$/month with a lot of various tools to help the website ranking like a PPC keyword tool for advertisers and topic-, organic- and advertising research.
Long-tail keywords are phrases that are three to four words long. This research is useful when a person looks for a very specific search phrase where there are more likely to buy. It is a lot easier to rank for long-tail keywords because of the smaller competition.
It all starts with the topic you want to write about on your blog. You should search for a head keyword which you use to find related keywords. Look for the popularity of each keyword and how difficult it is to rank for in the search engine. Make notes of the best keywords you searched for and decide afterward which fits the most as your blog post title.