The starting point: seed keywords and research tools
The starting point hasn't changed: a list of seed keywords, the most obvious terms tied to a product or business. Someone selling running shoes starts with "running shoes" or "shoes for jogging." From there, tools like Google Keyword Planner, Ahrefs, Semrush or Google's own autocomplete expand that list with variations, related questions and phrases people actually type. A handful of seed keywords can spin off hundreds of long-tail variants this way, longer, more specific phrasings with lower individual volume that, added together, can account for a sizeable share of the traffic actually within reach.
Every keyword that surfaces gets measured against three basics. Search volume shows how often a term is searched monthly, though it's an estimate, not a hard number: tools bundle variants together and round figures. Keyword difficulty (KD) measures how hard it is to compete against the domains already ranking. Cost per click, borrowed from Google Ads, works as a rough proxy for how much commercial value that search carries for the person typing it.
With those three numbers, the classic move is to find the sweet spot between volume and difficulty: terms with enough demand but without impossible competition. That's a necessary step, but it stops short. Two keywords with identical volume can be worth wildly different amounts to a business, depending on what the searcher actually wants. That's what the next section covers.
The seed keyword list is rarely complete on the first pass. The "People also ask" section Google shows directly in the results, an analysis of which keywords already send traffic to direct competitors, and above all the query report inside Search Console are three sources that almost never come up empty. Search Console has the advantage of showing exactly what people type when they already find your domain, including searches you rank for without realizing it.