For the E major chord, we can use our pinky to play the F# at the 2nd fret on the 1st string, creating an E Add9 chord (remember that one?). In general with these types of chords, it's often about playing the common chord voicing, and experimenting with whatever fingers are left over, and placing them on different notes to see how they sound:
Listen to the example below to hear this in context:
