1- Restart your phone at least once in a week( You can schedule for that if you want I can tell you, you wouldn't need to do it manually)
2- Have less app, which is usefull
3- Factory Reset your phone once in 3-4 month, It makes your phone smoother and feel new.
By following these things your samsung mobile always perform better, you won't feel bad like hanging problem, smoothness problem, I am saying it because I always follow these steps and I am using Samsung mobile since 2010-11.
Ofcourse you need to backup all your important stuff such as contact, photos, document, call history, call recording some important thing which you do have.
