The most effective approach is using apps that block access to social media during study sessions, like Freedom or Forest, which prevent you from opening Instagram and TikTok even if you want to; some also have a "focus" mode that gamifies the process (in Forest you literally plant a virtual tree while you study and it dies if you leave the app). Another strategy that works even better is putting your phone in another room during 45-50 minute blocks and using a tablet or laptop to access your study materials, so you avoid the temptation directly. If you can't do that, at least disable notifications from social media or create a "study" account with a complicated password that you save on another device, that way you break the automatic habit of scrolling.