They do no soaking of the fries first, and they overload the fryer so the temp drops and the fries are soggy. Double frying is the main thing though. Double frying dehydrates the fry some (there is chemistry behind it) in the first fry, then you cool it off, and fry again and the outside crisps up and the middle is soft. Then it also takes salt well. Most frozen fries taste better than in n out, and it's because they are typically par cooked first.