The topic is of course a bit misleading. There are only so many notes, and it's not the note itself that allows you to guess the song. Rather, it's something that makes the way the note is played unique. For example, is it extraordinarily long? Any unique effects on it?
Even easier: what else is happening while that note is played? A good example is Eagles, Midnight Rider. During that first note there is banjo playing. Makes it very distinctive.
So the easy way to win this game is to find songs that either have something strange happening to the first note or, better yet, something else happening along with that first note.