Don't define your target market as "we just need to get 1% of this $100B market".
Define your market as "for this $XM sub-niche of a sub-niche, we are the 800 pound gorilla that is the obvious choice."
You can always expand your target market over time, but start where you are strong.
Everyone understands this in theory, but it's hard to do in practice, because I think we have evolutionary aversion to "scarcity". So instead of thinking of it as "small vs large" market (when the small market is plenty to start with), think of it as "easy vs hard" sales and marketing. If sales and marketing is hard, shrink your market.
You can always expand your target market over time, but start where you are strong.
Everyone understands this in theory, but it's hard to do in practice, because I think we have evolutionary aversion to "scarcity". So instead of thinking of it as "small vs large" market (when the small market is plenty to start with), think of it as "easy vs hard" sales and marketing. If sales and marketing is hard, shrink your market.