From time to time, I refer to official Apple documentation. Some of Apple’s descriptions are right on the mark, and there is no point in trying to restate them. Throughout this book, I have listed the most important documents and guides in the official Apple documentation that every professional iOS developer should read.
For starters, I suggest that you have a look at the “iPhone Human Interface Guidelines” and the “iPad Human Interface Guidelines.” These two documents will tell you everything you should know about developing engaging and intuitive user interfaces for the iPhone/iPod and the iPad. Every iOS programmer must read these documents. In fact, I believe these documents must be read by the product design and development teams of any company that develops iOS applications.
iPhone Human Interface Guidelines: http://developer.apple.com/library/ios/#documentation/userexperience/conceptual/mobilehig/Introduction/Introduction.html
iPad Human Interface Guidelines: https://developer.apple.com/library/ios/#documentation/General/Conceptual/iPadHIG/Introduction/Introduction.html
I also suggest that you skim through the “iOS Application Programming Guide” in the iOS Reference Library for some tips and advice on how to make great iOS applications:
One of the things you will notice when reading Chapter 12 is the use of block objects. This book concisely explains block objects, but if you require further details on the subject, I suggest you read “A Short Practical Guide to Blocks,” available at this URL:
Throughout this book, you will see references to “bundles” and loading images and data from bundles. You will read a concise overview about bundles in this book, but if you require further information, head over to the “Bundle Programming Guide,” available at this URL: