Well done to those of you who are able to carry around a smartphone and regulate yourselves but some of us need to take more drastic action to cut it out.
I cut my phone use by removing most social media apps. I have also disabled notifications for most remaining apps, except for Facetime and iMessage (since I use them for high signal/noise ratio communication with friends an family).
So I have a SIM with a dumbphone but no smartphone. People can call and send me messages. Frequently I leave that at home too.
I do have an iPod touch though which i use for podcasts, as a camera, and for a few specific things like a banking app. But no messaging, social media or distraction-type things are allowed on there.
People often get a bemused or even aggressive reaction to those who cut out conventional device habits.