This is the first thing your users see, and probably the single most important visible part of your application. It is the first chance you have at making an impression and the best chance to help establish your brand.

You Must Promise. To call your mother, to help old ladies cross the road, and to turn your cell phone off at the movies.

Whether native or not, this is obviously one of the first steps on your way to OS X. Keep in mind that often, the functionality of your code has a lot to do with how your interface is designed. How many developers have come up with great functional ideas from working with their interface or looking at their competitors'? Start working on your Aqua compliance from day one. Don't wait until the last minute.

This is the first thing your users see, and probably the single most important visible part of your application. It is the first chance you have at making an impression and the best chance to help establish your brand.