USP = Unique Selling Proposition = a one line statement (proposition) that explains (sells) how your product or service differs (unique) from the competition. You can't know it unless you research your product as well as your competition. What does Federal Express say? Dove soap? You must know your basic offer before you can begin to persuade anyone to accept it.
What do those two companies say as their "slogan" and how can you make your product sell more competitively?
Round-up your prospects with a headline that makes them sit up and take notice and write simply, directly, and in the conversational style of your prospects. Who are you trying to reach? Housewives, business executives, children? You must know the type of person you are writing to. Write to one person from that group and you will speak to all people in that group.
How can you make them sit up and take notice in a conversational style? Give an example.