I recommend: . . .
Buying on or two oranges, pick the heaviest ones for their size, they should be on the firm side (not rock hard or soft, just slightly soft), the darkest, most even orange color you can find (NO GREEN on a navel) and then go out to your car and taste. If they ain't tasty, don't buy any more, better yet, take the orange(s) back to your store and ask for your money back and tell them WHY you want the money back.
Sorry, I am tired of bad fruit in stores!