Think about it. You sell yourself to your family, your husband, wife, partner, your friends, your work colleagues, your boss, mostly through your personality and your competence. You sell your ideas, your preferences, your wishes, your needs. Most of this of course occurs subconciously - it's an unseen process that occurs thousands of times a day everywhere around you.
Of course it's different in every case for every individual but the fundamental process is the same - you sell, they buy. And if you're a good salesperson, you'll get what you want.