Most HCI studies on digital overuse emphasize the negative impacts of technology, particularly smartphones and apps, which are intended to be addictive and habit-forming. Thus, the phenomenon of smartphone overuse needs to be thoroughly understood in order to design effective mitigation measures. Traditionally, technologies and apps are designed to have as little friction as possible, while this thesis seeks to explore the reverse mainstream innovation principles. The research commenced with an autoethnographic study, reviewing both commercial and academic digital well-being applications. This initial step was essential in identifying theoretical underpinnings and features of existing apps. To examine the smartphone usage patterns in terms of meaningful and meaningless use, and to understand the motivations behind such behaviors, a diary study was conducted with 20 participants aged between 19 and 40. Participants were asked to self-report their usage through an online form over a 14-day period, and to upload screenshots of automatically tracked data from their smartphones. Following this diary study, these participants engaged in co-design workshops where they were presented with examples of design frictions to limit meaningless use. They were then encouraged to generate ideas to shed light on novel design frictions to support meaningful use. To further explore the application of design frictions in real-world contexts and assess their impact on smartphone usage, an additional 20 participants were recruited for a user study. This study involved evaluating a bespoke Android mobile app in the wild. Participants were asked to install the application on their smartphones and use it for a few minutes over a two-week period. After each usage, participants completed an online form and at the end of each week they participated in a half-hour interview. This thesis contributes to the body of knowledge by informing designers about the functionalities offered by top-rated digital well-being applications and providing guidelines for the design of such apps. The thesis also contributes to exiting knowledge by highlighting the origins of meaningful and meaningless smartphone use. This has an important design implications mainly to support meaningful use rather than limiting meaningless use. A pivotal implication is the integration of a hedonic element into the design to potentially enhance meaningful use. Moreover, the thesis provides a nuanced understanding of the relative value of different design frictions, demonstrating how some can facilitate meaningful use and mitigate problematic use. Conversely, it also highlights that certain frictions may be inappropriate for application in specific types of apps.