To design my first app we used my Moleskine notebook to create lots of templates on a whiteboard and sketched out the pages. It was fun and I highly recommend this method. We erased and changed things constantly as we mapped out the app.

I used Photoshop as a tried and trusted tool to then create those designs digitally and manufacture the graphics. Teehan and Lax offer a great Photoshop template file which contains all the standard Apple UI components.

They also provide the component in a sketch format for Illustrator use:

Although it is possible to create your own controls, Apple is keen for designers and developers to use the standard controls (see my earlier comments on the HIG). It makes good business and usability sense to follow this advice, as it instantly gives the customer an understanding of how to navigate around the app without having to learn the UI. I worked closely with an Objective C developer to prototype the app in a kind of Pair Programming capacity and hope to increase my understanding of Interface Builder and X-Code to further facilitate this process in the future.

The app prototype is looking great and I’m looking forward to the fun and games of getting it approved and on the app store.