Niche

"Bookkeeping for dental practices" is a niche; "accounting services" is not. Narrowness lets you charge more, market more cheaply and get referred more often, because you become the obvious choice rather than an option.

Almost every beginner picks a niche that is too broad. If you cannot name three places your customers gather, it is not narrow enough yet.

The economics are brutal in your favour. A generalist bidding on a $2,000 project is one of forty quotes and wins on price. A specialist who has done the identical job eleven times quotes $6,000, wins on the first call because the client recognises their own situation being described, and spends almost nothing acquiring the work. Narrowness is the cheapest marketing available.

Test one before committing to it: can you name three places these people gather, three words they use that outsiders do not, and three things they already pay for? If not, you have a category rather than a niche. And it is a starting position, not a life sentence - you widen after you own it, which is the order almost everyone gets backwards.