I just did mine about a month ago with 20% film. 1 roll did all 7 windows for about $15. I think they came out great. I've also had windows tinted professionally on 2 vehicles, one came out amazingly perfect and the other not so good and 2 windows needed to be redone within a month.
On my MJ I pulled the door glass and did them inside, that way I was able to extend the tint all the way edge to edge to hopefully reduce the chance of it peeling up when the windows are rolled up & down...so far so good. On the back glass I made templates out of poster board and cut the film inside. The back windows have 1/2" wide dark strips on either side that give you some leeway with positioning the tint. Remove the latch, don't try to trim around it.
Clean everything really well first, use a razor blade on the glass and a lint free cloth. Then use a spray bottle filled with water and tiny bit of dish soap and spray it generously, both the windows and the film as you peel the backing away. That step is especially important to prevent bits of airborne dust from getting sttracted to the film's adhesive. You can slide the film around and into position once on the glass with everything good and wet. Then use a quality soft plastic squeegee and take your time squeezing the water out to the edges. Spray both sides of the film to help the squeegee slide better.
I'll post a pic when I get home. Like anything else if you take your time and concentrate on the quality of your work you can do a near professional job yourself.