1: After iOS upgrade to iPhone 4, my contact list is gone. Is it possible to recover?
2: I deleted some text messages on my iPhone 4S and now need to recover them.
3: I lost my iPhone, how can I recover my photos? They are important to me.
4: Is there a way to recover iPhone videos if I deleted accidentally?
5: I deleted some messages on my iPhone 5 and now need to recover them.
6: I haven’t backed up iPhone, how do I recover lost data after accidental restore?
And More...

Most people want to recover iPhone data with free iPhone data recovery program. However, it is hard to find a good one. But you can recover your data from iCloud without paying any money.
Your iPhone data can be restored from iCloud when setting up a new device, or after erasing all data from a device using Settings -> General -> Reset ->
Erase All Content and Settings.
You will be prompted by Setup Assistant by a new iPhone to set up as a new phone or restore from backup.
Make sure your iPhone is connected to Wi-Fi and plugged into the charger.
Select the option restore from iCloud Backup.
Enter your iCloud account and password.
Choose the recent backup you wish to restore to your iPhone.
Enter any passwords required when prompted.
You will see a progress bar with time remaining as iCloud restores your data. When this is complete, iCloud will begin to download apps. You will see a progress bar under apps that are being downloaded. If you need a specific app first, tap its icon to move it ahead in the queue. To check if the restore is finished, navigate to Settings -> iCloud -> Storage & Backup.
iTunes Match users can download albums, playlists and songs from iCloud when the restore is finished.
If you haven’t made a backup before, I’m afraid that you must go to data recovery tool. Although there is no any free iPhone data recovery software, it worth to pay a little for it.

Tutorials for iPhone Data Recovery:
1. iPhone data recovery- 3 simple steps to recover iPhone Data
2. Do data recovery for iPhone with iPhone data recovery software
3. iPhone data recovery without backup- How to Recover iPhone data without backup