WHO . . . do you want to attract to you?
The people who can best understand, value, desire and afford the beneficial difference your Mission suggests, of course!

You want people who “see themselves” as part of any group that resonates with your Mission.  So consider defining your NICHE around any of the following:

Industry –– e.g. banking, financial services, healthcare, etc.
Function –– e.g. accounting, IT, sales, marketing, HR, finance, manufacturing, etc.
Situation –– e.g. relocating executives, turn-arounds, new start-ups, etc.
Problem –– e.g. employee skill deficiency, inadequate sales and revenues, etc.
Trend –– e.g. social media, online marketing, tele-commuting, distance learning, etc.

Your MISSION suggests your MARKET.  Your MARKET validates your MISSION.

Knowing WHY you’re valuable, suggests WHO cares and WHERE you’ll find them