The icon is the very first impression a user gets, along with the app name. The name must be unique, and it may differ from the one that is shown on the homescreen of devices, below the icons. It's often good when these two names are the same. whatsapp number list But, for example, if you submit a new calculator, it must have a unique name that's displayed on its page on the App Store, but for users it would be fine if entitled simply 'Calculator', as it is, on the homescreen.
What's the main showcase of your application on its App Store page? Correct, screenshots. Your app can have up 1 to 5 screenshots on the page. Surely, if your app is universal, supports both the iPad and iPhone/iPod touch, make sure to prepare separate screenshots for those. The elongated 4'' screen of the iPhone 5 also makes the difference, in comparison with its 3.5'' counterpart. But hey, there's one more useful thing you should know. Screenshots must have fixed sizes - those of the devices, that's a rule. But the images don't have to be actual app screenshots. You may use this rule in a creative way, if it's reasonable for your software product.
What else should your app have to be ready for submission? That's metadata. This means the abovementioned name, app category (primary and secondary - for example, for games), version number, a short description, keywords and a support link. Apps with sign-ups require a demo account for the Apple team, so they wouldn't have to sign up from scratch. When you will roll out updates (which is vital and not as painless as submitting a brand new app), you will inform your users with the help of 'What's new'.