There are many ways to recover data from a Samsung Galaxy phone.
1. Do you have Google account? If you have, and made a back up for your data, you can restore data by your Google account.
2. Samsung KIES, if you have installed a KIES to your computer, when you connect the tab to computer, KIES may make a backup for your tab automatically, so, you can try to find whether there is backup on your computer.
3. Maybe you installed some backup apps to your tab, such as Titanium, and have maken a backup, you can restore data from the apps.
4. Finally, if you are so unlucky that there are not any backup in your tab or computer, I am afraid that you should recover your data by recovery software. There are so many recovery software you can choose, such as Recuva, which is free, but it can not recover 100% data. You can choose others as well. You can find more here: http://www.any-data-recovery.com/topics/mobile-devices/recover-samsung-galaxy.html