This report delves into current design and usability practices for software interfaces, with a focus on user experience (UX) and human-computer interaction (HCI). It examines key principles such as color usage, navigation, visible language, organizational layout, consistency, and simplicity, along with justifications for their implementation. The report references academic articles and highlights the importance of effective UI design in enhancing user engagement and achieving business goals, such as customer acquisition and retention. It also discusses the advantages of a well-designed UI, including lower development and support costs, increased productivity, and improved customer satisfaction. The report concludes by emphasizing the significance of adhering to established guidelines to create user interfaces that are both effective and user-friendly. Examples of real-world applications like Adidas are provided to demonstrate the successful application of these design principles.