[Galaxy Tab S Q&A, Help & Troubleshooting] xLima:
Instructions

MAKE SURE TO DOWNLOAD THE FILES FOR YOUR SPECIFIC DEVICE (T700, T705, T800, T805, etc.)

You will need Odin (This is the software that will allow you to install the root and other files [FLASHING])

CF-AutoRoot (Will provide Root access for your device): You will be flashing this with Odin

Optional: Install custom recovery TWRP. This is also done with Odin. This will allow you to make backups and flash .zip files, including custom roms, apps, etc.

Just google for guides on rooting Samsung Galaxy Tab S. They will show you step by step on how to do the Odin flashing, PDA, settings, autoreset or not, etc.

I recommend backing up your device at this point. Reboot into recovery (instructions will be in the rooting guides), go to backup and backup everything for now. In the future when you feel comfortable enough that you can/will select to only backup what you deem necessary.

Your device is now rooted, the first boot after installing CFAutoRoot will take awhile +/-3 - 5 minutes.

Now download Titanium Backup, and you can google or search XDA for a list of "safe" things to uninstall. Just go into TitaniumBackup and look for the app you want to Freeze (This will prevent the app from running but it will NOT delete it, thus it will still take up space) or Remove.

Busybox: Will be required by certain apps.

Optional:

Link2SD App, this allows you to install/move/link your apps to the SD Card, it essentially frees up your internal memory of the device and tricks the device into installing apps and their data files onto your second partition of your External SD Card (Google or Search XDA for guides on Link2SD). This will allow you to install a lot more apps than you normally would be able to. (Example: Vice City, San Andreas, Plants vs Zombies, etc. I mention these because of their large data size). Not all apps will work when linked, just trial and error. I can't seem to get Word, Excel, Powerpoint linked to my SD Card without at least one of the failing, same with Facebook. You will have to test each app and see what files you can link/bind and which you can't.

Adblock Plus: Self explanatory

Xposed: A bunch of customization options for your device

ES File Explorer Pro: The best file management/directory app IMO

Greenify: Battery saver

Aptoide: Secondary App Store

Hancom Apps: I feel these work better on occasion then the Microsoft Office apps (Example large excel files with multiple formulas and filters)

NovaLauncher: Custom launcher, a lot more customizations then TouchWiz will provide you. (Your home screen)

Tasker: Limitless possibilities with this app (Search google/XDA for info)

TWRP Manager: TWRP Recovery app.

VLC: Video player

4way_multiwindow: This will allow you to have 4 apps open at a time and 3 apps "minimized", this also allows floating windows (Moveable apps running in "windowed mode" essentially.) There is an aesthetic bug when minimized, I have not found a fixed version of this yet, maybe others can provide link. Just load up TWRP manager and choose install, and select the .zip file and it will reboot into recovery and install the file for you. Or you can boot your device into recovery and install it the same way. I am attaching the .zip file.

If you are happy with your device up to this point, I would create another backup after you are done with the initial set up and have installed the apps of your choosing. Save a copy on the device, PC, NAS, etc. just in case you lose one of your copies. Some TWRP versions do not allow you to backup directly to the external SD Card, you may have to backup into the Internal and then transfer the information over to the external SD Card.

Good Luck.