For example, if a swimming pool business is trying to rank for "fiberglass pools" -- which is receiving 110,000 searches per month -- this short-tail keyword can be the one that represents the overarching topic on which they want to create content. The business would then identify a series of long-tail keywords that relate to this short-tail keyword, have reasonable monthly search volume, and help to elaborate on the topic of fiberglass pools. We'll talk more about these long-tails in the next step of this process.
Lastly, it's important to remember that paralysis by over-thinking is a real issue some struggle with. There's no pill for it (yet). Predicting perfection is a fool's errand. Get as close as you can within a reasonable timeframe, and prepare for future iteration. If you're traveling through your plan and determine a soft spot at any time, simply pivot. It's many hours of upfront work to get your strategy built, but it's not too hard to tweak as you go.