Identify a problem that you wish to investigate and your first theory that helps you understand the problem by evaluating your problem. List the ways your first theory is connected to the problem you are investigating. As an example, you may question the problem of individual anxiety and depression as it pertains to the cognitive dissonance theory: the theory that suggests that the difference between the things a person says and the things they do causes unhappiness and personal anxiety.
Select a second theory that has a connection to either the problem you are focusing on or the first theory you are considering. For instance, you may want to consider Piaget's constructivist theory: the theory that states that each person is a construct of their experiences and history.
Study both theories thoroughly, listing important elements in each theory. As an example, you may note that the cognitive dissonance theory identifies the cause of the problem you are investigating, the depression and anxiety in some people. You may also note that the constructivist theory suggests a method by which a person becomes who she is from a lifetime of experiences. Note the location from which you gathered your information, so you can go back and reread anything you need later.
Connect the two theories based on the information that you obtained about them. Consider multiple ways to connect them. For instance, if the constructivist theory defines the way a person develops and cognitive dissonance describes the difference between action and thought, then together the theories suggest that the anxiety of cognitive dissonance results from the development stages, suggesting that people learn to act one way and think another.
List the implications of your combined theory and suggest ways to use this information to address your problem. As an example, feeling anxiety or depression, extending from learning to act one way and think another, suggests something important about teaching children to discuss their emotions openly and the benefit of an honest relationship between parents and children.