My cheatsheet on how to set up Protocols + Delegation in iOS:

1. TargetViewController.h:
   

   • Create protocol 
     @protocol TargetViewControllerDelegate
     @required
     …methods…
     @end
   • Create delegate
     @property (weak, nonatomic) id delegate;

2. SourceViewController.h:
   

   • #import “TargetViewController.h”
   • Conform to protocol:  <TargetViewControllerDelegate>

3. SourceViewController.m:
   

   • Add #pragma mark – TargetViewController Delegate
   • Define methods and dismiss TargetViewController
     [self dismissViewControllerAnimated:YES completion:nil];
   • In prepareForSegue,
     if ([segue.destinationViewController isKindOfClass: [TargetViewController class]) }
     TargetViewController *targetViewController = segue.destinationViewController;
     targetViewController.delegate = self;
     }

4. TargetViewController.m:
   

   • Define methodName as [self.delegate methodName];