The quality of social interaction is crucial for psychological and physiological health. Previous research shows that smartphones can negatively impact face-to-face social interactions. Many HCI studies have addressed this by limiting smartphone use during social interactions. While these studies show a decrease in smartphone use, restrictive approaches have their drawbacks. Users need high levels of self-regulation to follow them, and they may cause unintended effects like withdrawal symptoms. Given the impact of smartphones on social interactions, both positive and negative, new solutions are needed to reduce the negative effects of excessive smartphone use without resorting to restrictive methods. This thesis aims to explore smartphone use behavior in the context of social interactions and relationships using various data collection techniques to understand how this behavior hinders and supports social interactions. We began with in situ observations and focus group sessions. Based on insights from these steps, we developed two research prototypes to improve social interactions without restricting smartphone use. We gathered user feedback, reactions, and concerns about these prototypes through user studies. Finally, we evaluated how these prototypes affected conversation quality in social interactions through an experimental user study. This thesis contributes to the field of digital well-being by offering user insights, design implications, and approaches that can guide the creation of solutions to enhance social interactions in the presence of smartphones.