To get from good to great, I believe we have to constantly learn from others, and become early adopters of latest techniques and tools. Other than Apple’s documentation site, these are those that contains valuable articles and resources that help us to make the leap.

Let’s start with some original content blogs:

A monthly updating issue contributing from world-class iOS engineers. Expecting high quality and in-depth articles on certain topic, they also provides a subscription-based newsstand iPad app. Found by Chris Eidhof, Daniel Eggert, and Florian Kugler.

Recently hot site that disassemble and reconstruct innovative patterns and UI found in famous apps. Provide procedural articles and code repositories for their experiments. Written by Sam Page.

It’s sad that the author decided to put a stop on the site, but the old tutorials are still worth to read. ☹

Class by class in-depth explaination and with sample code. Talks about coding styles and cutting edge approaches of class usages and implementation. Created by Mattt Thompson who published AFNetworking, now managed by Nate Cook.

Personal blog of the author of the most popular commercial PDF library on iOS that has been used by famous apps like Dropbox and Evernote. Contains crazy hacking materials and debugging resources to learn and apply for development.

Blog focused on sharing his personal experience, discussion on code style and API design, and occasionally revealing interesting private classes that used by Apple.

Personal site from the co-author of objc.io. You’ll find a number of articles about performance measurements and discussions, including UI drawing to multi-threaded Core Data.

Written in an interesting Q&A format, contains lots of deep questions not just on Objective-C. If you’re those kinds of developer have questions on rebuilding a fundamental class like NSObject, ask Mike Ash.

Random but useful bits of iOS development logs and insights from the iOS developer’s team at Tumblr.