For non-profits, businesses, and even political campaigns, online marketing is crucial for reaching both new and existing audiences. Why invest in billboard ads when online advertising offers targeted reach and measurable results? There is a reason why Google and Meta are two of the largest companies in the world. These platforms have billions of users. But how do advertisers find the right users to advertise to? During my senior project, I have been exploring audience-targeting strategies that organizations can implement across advertising platforms. By having interviews with employees who work for companies such as Meta and LinkedIn, I have been gaining a greater understanding of the marketing platform industry. Additionally, throughout my onsite experience with Digicom, a growth marketing agency based in New York, I have been conducting campaign data analysis for a variety of their clients. During this experience, I have been learning various audience targeting strategies that businesses can employ to maximize the effectiveness of their advertising campaigns.