One of the few features that I've liked in Visual Studio that XCode doesn't have is the ability to define regions for code folding. It's nice to have regions of code that are logically grouped that you can collapse when you're working on other parts of the same method. (Of course, regions also work across methods, but this hint won't address that.)
Fortunately, XCode allows for block folding (which the versions of Visual Studio I've used don't have), which allows you do to something like this:
//region I want to fold
{
...code...
}
This defines a statement block that you can fold. When folded it ends up looking like this:
//region I want to fold
{...}
One caveat here... don't define any variables in that block that you'll need elsewhere. The statement block defines a local scope for any variables declared. This might be want you want, but it may also cause scoping issues. The compiler will probably warn you about this, however.