Before you add the declarative match rules, review and understand your data. Your data might be incorrect, inconsistent, and have missing values. Review the data for quality of the data values, consistency, uniqueness, and logic.
For example, to add declarative match rules to match individuals, you must understand the attributes related to individuals. If the First Name and the Last Name fields have missing values, it is not ideal to base the rules on these fields because of missing values. The Full Name field might have values for all records and is good to use as a match field in the rules.
You can use the Address fields, such as Address Line 1, City, and Postal Code, as match fields in the rules. The Address fields would help identify duplicate records. Based on your review, you can add rules to match individuals based on the name and address fields.