Here's a quick reference guide for how to fill out the residential contract of sale. This video provides a step-by-step guide on how to fill out Maryland's Residential Contract of Sale form.The terms of the contract must be agreed upon mutually. If you wish to make an offer to purchase the property, you may contract with a licensed real estate agent to create and negotiate an offer on your behalf. How to fill out the Maryland Residential Contract of Sale Agreement? A valid offer, acceptance of the offer, and adequate consideration; Legal capacity of the parties to enter the agreement; Legal purpose.