[Galaxy S 4 General] el_garicimo:
Steps 1,2,3: find device model, research how to gain root, ROOT!

Step1: figure out what your device is- specific phone and model

ans: for example, my friend's phone I am setting up for him is the Samsung Galaxy S4 model i9500

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Step2: figure out how to root (gain root access to) your device

ans: Off all the devices on xda forums (http://xdaforums.com/index.php?tab=top), found my device ( http://xdaforums.com/galaxy-s4) , found the proper forum (http://xdaforums.com/galaxy-s4/help) , then searched in that specific forum to find the proper thread http://xdaforums.com/showthread.php?t=2419762 , see Q4

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Step3: Follow instructions, root device

ans: Instructions are at http://xdaforums.com/showthread.php?t=2292615

NOTE: You must have the proper USB drivers installed, meaning either installing the sdk (software developer kit) from google and getting adb (android debugging bridge) set up (this is the best way to do it, really, especially if you want to mess around with phones more...tutorial on how to setup adb here http://androidcentral.us/2013/08/how-to-install-android-adb-and-fastboot-on-windows/ ) . If you can already transfer music and stuff from your computer, it may work without adb. Be sure your USB cable is not too beat up, and if possible, is the one that came with the device.

adb is very useful for communicating between pretty much any android phone and your computer. You can use it to push files on the computer through the terminal interface, even if the phone's file system doesn't show up for whatever reason on the computer when you connect it via USB ( more on that here http://log.amitshah.net/2012/05/using-adb-to-copy-files-to-from-your-android-device/ ), and a cool little program to send files from your computer to the device in a slightly more straightforward way, if you already have adb installed (http://www.xda-developers.com/android/push-files-to-your-device-with-quick-adb-pusher/)

Also, make sure you have USB debugging enabled. It should be in the Develpors options, which you may have to "activate" to see...see here http://gs4.wonderhowto.com/how-to/enable-hidden-developer-options-your-samsung-galaxy-s4-0146687/

If you are rooting a samsung device, you will probably have to use a program called ODIN. Other android devices allow you to do root through a method called flashboot. In general there are tons of ways to root devices, just make sure the one you are using has been tested and you follow the instructions exactly.

CONGRATS! you are rooted. That's half the battle. Rooting the phone will add a "Super User" app of some kind, which will basically controll which apps have access to the internal files of the phone (located on the "root" of the phone's flash drive). Some apps that are very useful for flashing custom ROMS (like ROM manager) and backing up your apps and their associated data (like Titanium backup) require root access, so you'll need to have rooted your phone first, and then when you open those apps for the first time, tap "allow" when it asks about granting root access.

some cool apps can only be downloaded if your phone has Root, like this gameboy emulator: https://play.google.com/store/apps/details?id=eu.codlab.src.game&hl=en

and here are some good Root apps to have, apparently

http://www.youtube.com/watch?v=jX4ir9r84YA