A lot can be learned from using existing code templates. Below is a list of source code resources to consider when starting a new project or updating an existing one.
These are a list of technical blogs maintained by some of the best in the industry.
A periodical about best practices and advanced techniques for iOS and OS X development.
NSHipster is a journal of the overlooked bits in Objective-C, Swift, and Cocoa. Updated weekly.
Ray Wenderlich - Tutorials for developers & Gamers
Although we've used GitHub as a way to store our Git repositories, you can also use GitHub to find other developers' public and open source repositories. Here are few favorites:
Find what repositories the GitHub community is most excited about today.
Elegant HTTP Networking in Swift
The better way to deal with JSON data in Swift
Apple has WWDC (World wide developer conferences) each year. In addition, they recently have begun Tech Talks which are smaller conferences aimed specifically at iOS developers.
Here are some direct links to those resources: