The end goal may be to make sales, however your online objective has to be specific. For example, do you want more traffic? If so, do you want mere webpage hits or do you want the traffic to be warm and lead-like? You may want people to like, comment on, or share your post. You may want people to click-through to your page and enter their emails.
What is that individual interested in? How does that individual behave? How old is that individual? Is that individual a specific gender? Does that individual rent? How much does that individual earn? Please go into as much detail as you can - as if the person were standing right in front of you.