Generally when you can construct a sentence with 'whose', 'of whom' and 'about (in final position)' there are chances it is translated with 'dont' in french.
- the boy I told you about : le garçon dont je t'ai parlé
- the boy whose homework is missing : le garçon dont la copie manque
- the boy of whom you know the parents / whose parents you know : le garçon dont tu connais les parents
This is the easy hack, yet it's possible you'll find sentences that do not enter this pattern, 'dont' covers a wide variety of constructions in english.