Increasing your odds
If you present a single proposal to a client, you only give them the option of accepting or rejecting.
Source: Sales author Emma Snider
But if you present them with two or three different variations on your proposal, suddenly you've doubled or tripled your odds of receiving some form of a "yes."
So in negotiations don't just ask if they'd like to sign the contract, ask if version A or version B or version C is preferable.