I have unfollowed everyone except close family and friends who I actually want to talk to.
This also works with groups you're part of. They stay on your account but won't show up on your newsfeed all the time and distract you from your important family.
You could delete the app for Facebook and have to log into the browser page each time.
Over time you may change the habit of being constantly logged in and only check at a certain time of day.
I've also got an app called ActionDash which I can set app time limits. For example I've set my internet browser to 2hrs limit a day so I'm forced to only go on for important things.
Hope this helps.