As the competition in the iPhone application market is getting more and more intense it is an important challenge for every application developer to build a successful application. First you have to find your niche and provide the perfect application for it and then you have to deal with some of the problems the App Store comes with.
Getting an update to the store can be a very lengthy process. And if you have new features it might be even possible that your App is rejected by Apple. So if you have an critical bug which you can fix in 5 minutes it might be possible that your customers have to wait for weeks to get this fix. There is now a way to contact Apple if you have an important bug-fix but I don't know how well it works. The only solution for this is to test as best as possible and then test again.
When a crash occurs and the user decides to send the crash report to Apple you can access these reports in your iTunesConnect account. But it is up to Apple when they provide these reports and they only provide the reports for the latest version. That's why we decided to integrate plcrashreporter into our next application. After a crash the application recognizes it on the next start and provides the user the possibility to send the crash report to our server. Now we have instant access to crash reports and can start fixing the bug. We even have the possibility to provide feedback to the user, for example if the bug is already fixed. For the admin tool and the plcrashreporter integration we used the CrashReporterDemo (edit: It's called QuincyKit know) which provides all the functionality we need.
User feedback is very important for the success of an application. Bad iTunes customer reviews can destroy the sales of an application. The reality is that you will get more bad than good reviews. This is mainly because when the user deletes an application on his iPhone he is invited to rate the application. Most of the times these ratings are one star ratings because the user don't like your product and removes it. People who are satisfied with your App probably won't do a review because most of the time people do write reviews only when they want to complain. To achieve more reviews it's maybe a good idea to ask the user to write a review for the application after a certain time. Let's say after 4 weeks of application usage the user gets an dialog saying something like "Thanks for using our application! If you like it please rate it in iTunes". By doing this it would be only one click for the user to get into iTunes where he can rate or review your application.
All those steps can help you to hopefully improve your application success and to build a better product for your customers.