roll the window down a litlle bit so u can start at the very top.
take a hair dryer or a heat gun if u have one and start heating the tint (from the inside) at a corner.
Working your way across and down the window heat a section of tint then pull it off slowly. If you do this right and wait for the tint to heat up enough you wont even have any residue on your windows.
then when you almost to the bottom of the window just roll it up and remove the rest of the tint..
Like i said, if you give the tint enought time to heat up properly this will make this job a lot easier for you
if u mess up a little and theres a lot of sticky stuff still left on your window you can put a nice coat of windex or i personally like this orange disolve spray and take a razor blade a just scrape the glue off the window.
I have seen people use a spray bottle half ammonia and half water, spray it on the tint then put a black trash bag over the tinted window and make sure bag is pressed firmly up aginst tint,cracking the window down a bit then back up so the bag his held in place,leave out in sun for a few minutes until the back gets warm then peel the bag away and tint should peel off along with bag leaving no glue residue. I have never done this personally but have seen it done.hope this helps
if u got/can get a steamer those work great. i used that twice. take your time and peel slow. it will be easy to peel the tint off quick once you get a grasp but DONT, you will be left with alot of glue thats a bitch to clean off.