If you have an iPhone with iOS 6 and want to update to iOS 7 you will want to make sure you minimize all risks of losing important data, pictures and other items before you begin the upgrade process. You will also want to update all apps and software to assure a smooth transition. This way you can be assured that not only will your most important information be saved in case of any glitches, but the updating process itself will run smoothly.
The first thing you will want to do is make backups of all your data to iCloud or iTunes and it also helps if you take the time to remove old data from your iPhone that you no longer want or need. While you are backing up your information and removing data from your iPhone 6, you will also want to make sure that all of the apps you are going to keep and iTunes is running at the most current versions. This way, any incompatibility issues from running outdated apps or iTunes software will be avoided.
To update iTunes by opening it on your computer, clicking on “iTunes” in the upper left hand corner of the screen and then clicking on “Check for Updates”. After iTunes is updated, you can then update your apps by clicking on the “Apps” tab in iTunes and choosing “nn updates available” in the bottom right of the screen. While you are updating your apps, make sure they all show up in your iTunes library so you can install them on your iPhone iOS 6 after you update to iOS 7 if you need to. You can do by signing into the store menu on iTunes and clicking on “Purchased” on the right hand side of the screen. If you see apps that mention they are “Not on This Computer” go ahead and download them.
After you have backed up all your data to either iTunes or iCloud and updated iTunes and all your apps, you will want to perform a clean device start. To do this, make sure all applications are removed from the running app list and then reboot your iPhone by pressing on the power button. When your iPhone is booted back up you can then perform the upgrade to iOS 7 with the assurance that if anything needs to be reloaded afterward that you can quickly and easily download the most current backup.
Source GigaOm