Relying on the elaboration likelihood model of persuasion as our conceptual framework, we argue that applied interventions can be designed by considering two fundamental mechanisms that contribute to attitude and behavior change: Elaboration and validation. One way that interventions can produce behavioral change is by creating strong attitudes that stem from high elaboration of the intervention content. Elaboration is determined by many variables such as the perceived personal relevance of the intervention. Using examples from research aimed at promoting healthy eating and reducing prejudice, we show how increasing elaboration is critical for understanding both short and long-term change. A second technique to enhance the effectiveness of interventions is to increase the perceived validity of the recipient’s thoughts in response to the intervention. Like elaboration, many variables can affect thought validity, such as feeling empowered. We illustrate how a particular treatment can produce the same initial response (e.g., positive thoughts) in recipients but lead to different behavioral outcomes depending on how people perceive the validity of their intervention-relevant thoughts. Understanding how the processes of elaboration and validation work reveals that some interventions that are thought to be universally beneficial (e.g., inductions of happiness, self-affirmation techniques, empowerment treatments, and self-distancing) can sometimes increase influence but can sometimes decrease it.