If you prefer reading instead of watching videos, visit Ray Wenderlich tutorials (http://www.raywenderlich.com/). The site is tutorial oriented and teaches you how to solve a specific problem. The advantage of it is you can learn new components and you end with a simple finished product. They also sell books and videos with additional tutorials not published on the site.
After you pick up the basics, I strongly recommend to keep up to date with the newest updates and libraries. I like reading the following newsletters: