If you are one of those people like me who will want to get their hands on iOS 7 tomorrow (18th September 2013), that is the time in the USA, it is often released in the morning, West Coast time) then it is a good idea to make sure you have backed up your device like your iPhone, iPad or iPod touch and made sure all the apps are up to date.
There is a school of thought you should start from fresh when upgrading to take advantage of the new features, however, I am going to upgrade keeping what I have.
Here is some advice to help you out, remember you do upgrade at your own risk.
For backing up I use the iCloud but if you are not then you need to back up on your computer too. As it happens I do a backup on the computer too, can’t be too careful. This may all be time consuming but if you lose something during the upgrade to iOS 7 then you will be pleased you did. If you are using iCloud make sure you have done a backup, go to Settings -> iCloud, scroll to the bottom and click on Storage & Backup, scroll to the bottom again and click on Back Up Now, usually a good idea to do when you have Wifi unless you have a data package on your mobile account that has plenty of data available, however, I would recommend Wifi. It should automatically backup when charging and with a Wifi connection, in my case it usually backs up overnight, every night.
Many apps have been updated to work on iOS 7 because either they take advantage of new features or do not work well. For this reason it is a good idea to make sure your apps are up to date. Make sure they are by going to the Apps Store, choosing updates and updating your apps, you can do this before you upgrade. This is what I do.
Usually with an upgrade of an iOS comes a new iTunes, if you are prompted to upgrade iTunes then this is probably a good idea.
If you did start from fresh or lost some apps, music, films or TV shows then this video shows you how you can get back what you purchased.