Here are some of my personal Xcode snippets that I use in development. I'll be updating this list as I go, and would definitely appreciate any additions/modifications to simplify some of the tedious things we write in Xcode.
paro == @property (nonatomic, assign, readonly)
parw == @property (nonatomic, assign, readwrite)
pcro == @property (nonatomic, copy, readonly)
pcrw == @property (nonatomic, copy, readwrite)
psro == @property (nonatomic, strong, readonly)
psrw == @property (nonatomic, strong, readwrite)
unavailable == __attribute__((unavailable("Please use ....")));
weakify == __weak typeof(self)weakSelf = self;
strongify == __strong typeof(weakSelf)strongSelf = weakSelf;
To install, simply move the snippets to your ~/Library/Developer/Xcode/UserData/CodeSnippets folder. Create the folder if it doesn't exist.