For now, every iOS user knows that the untethered jailbreak for iOS 6.0, 6.0.1 and 6.1 might be released this Sunday, February the 3rd. If you are already on iOs 6.0 or 6.0.1, you might stay there and wait for the jailbreak but it is always good to stay updated, so you are advised to upgrade your device to iOS 6.1.
If your device is running firmware version < 6.1, then you already know that it can be updated via OTA by going to Settings > General >> Software Update. But rather doing that, you are advised to update it using iTunes to jailbreak your device smoother and without any hassles. Just follow the instructions below.
Method 1 (Automatic):
Just plug the device into your computer and run iTunes. iTunes will automatically detect that your device needs to be upgrade to iOS 6.1. Simply hit download and upgrade to start the process.
Method 2 (Manual):
Step 1: Go to this page. Download 6.1.0 firmware file for your device and keep it somewhere on your computer.
Step 2: Plug your device into the computer and run iTunes.
Step 3: Shift + Click on Restore button (Mac users: ALT + click) and select the firmware file you downloaded in step 1.
Now Sit back and see your device being upgraded to iOs 6.1. It usually takes around 15 minutes so keep patience.