The Bag to Choose
The single most important step in playing this game is to choose which bag to look at. You should choose the bag with the label "apple, orange".
If, for instance, the fruit shown is an apple, you will instantly know that the correct label for this bag is "apple, apple", because the correct label cannot be "apple, orange" (as that label is incorrect), nor can it be "orange, orange" (as there is an apple in the bag). After that, you can easily figure out the correct labels for the other bags.