ZEP window cleaner (I get it from Home Depot) and a CLEAN cotton terry cloth bath towel. I swear by it. Works great. No smears. No residue. When the film returns to the glass, then do it all over again. I have a 2012 and have done it twice in the last two and a half months to keep up with it.
A couple weeks ago I bought and used denatured alcohol per the instructions: 4 oz per gallon water. It was immediately better. I'm gonna do it again this weekend (OK, I intend to do it and we all know what the road to hell is paved with... ) because I left some residue before. But I've been fighting this for months and finally got some relief. Another member on here suggested it and I'm beholdin' to them!