As I've been learning Amharic I've been simultaneously learning ObjectiveC and writing my own language-learning application Amharic Pocket Guide. While both are going well, and I wanted to share a few things I've found helpful in iOS Development.
If you have seen my Personal Annual Report then it's no surprise that I like data. When it comes to iPhone Applications, I rely on Flurry to give me information about session length, and how certain application features are being used. Knowing how long people are using the "Quiz" in Amharic Pocket Guide has been helpful in learning how to improve it. Flurry also proves it's weight in gold when it comes to tracking down crashes or other unexpected events in your application.
While iTunes Connect has improved over the years (and their mobile site has as well), the best source for sales metrics is App Annie. They will download your sales reports for you each day, and track app store rankings and reviews, which is more information than apple provides.
The one thing that iTunes Connect Mobile is perfect for is for getting push notifications on application state changes. There is nothing better than knowing the exact instant your application is Approved, and there is nothing worse than knowing the exact instant your application is Rejected.
Every developer has a love/hate relationship with AppStore Reviews. Developers love them because good reviews can really promote an application, unfortunately misguided reviews can hurt an application far more, and there is no direct way for a developer to respond. If you don't have a good channel for users to contact you, then user issues end up in AppStore Reviews.
I've found the following approach good at helping to solve this.
1) Make sure there is a prominent "Report a Problem" or "Contact Support" button in the application. Typically I add a button that just pre-populates an email to a support address. This small detail can head off users that are confused or would otherwise need to vent in an AppStore Review.
2) Use a library like iRate to help prompt regular users to write a review. It's not worth pestering happy users, but you should encourage them to write a review.
3) Make an application website, link it from the App Store, and from inside the app, and have a way there to contact you.
I mentioned above that App Annie does a good job of pulling in reviews, but if you need something more comprehensive, there are scripts available to scrape the reviews yourself.
It's a fact of life (for now) that applications will be cracked and installed for free on jailbroken devices. One way to treat this is as an extended trial. I've seen it happen that if you can shut off old versions after releasing a new one, and you prompt users to update that many will (almost 20%) will just purchase the new version from the AppStore because they are not able to upgrade. iVersion is a library that can help with the code to check if a newer version is available, and prompt the user to update.
There are a bunch of things I find myself using regularly when doing ObjectiveC. I no longer know how I found some of them but here are the things I use: