If you have an iPhone you may already be well aware of and using these tips, but just in case, here's an article discussing a few. One of my favorite tips is silencing incoming calls unless they are in my contacts list. Really helps with so many robocalls existing. One must be careful, though, to add the phone # for a new contact -- say, a new doctor or dentist, or you might miss their incoming call.
Jim Hamm
10 Great iPhone Features You Should Be Using (howtogeek.com)