Account-based marketing is rooted in the premise that not all accounts are equal, which means that accounts need to be prioritized. Account-based marketers should start with a list of accounts that are high priority for the sales leader and augment this list based on their own due diligence. Accounts should be scored against three indexes — opportunity, achievability, and cooperation — to ensure the best chance of success. In this report, we describe a methodology for selecting accounts for a one-to-one ABM program and outline the insights that an account-based marketer should gather and apply to prioritize and score accounts.