I agree with the others. Have a pro do it. If you buy a high quality tint film from a pro shop, they will often give a lifetime guarantee (as long as you own that vehicle) We have a local shop here called Sunscreen International that offers a lifetime guarantee on their top of the line tint film.
If you have ever tried to peel off old bubbled-up tint screen, or pay to have it done, you will appreciate the value of a lifetime warranty that cost you nothing if they have to redo your windows 5-10 years down the road. It's well worth the extra cost to have it done and guaranteed.
...Rich