to build on what Dave is saying.....we know the song is in E, so listen for the bass notes of the chords. if you know hot o harmonize a major scale, you should be able to figure out it out pretty quick. the second i i hear the bass note in a song, i know what the chord should be.
music only does so many things within the structure of the given key (unless it's something that's really out there)........as your ear develops you'll instantly recognize extensions in chords, slash chords, etc.