Notice the thematic element of "Eleanor Rigby". The above main phrase of the tune is an unusual five bar phrase, broken into three smaller phrases. The first phrase is bar one, the second is bars two to four, and the last is bar five. Each phrase begins with the rhythmic figure of three eighth notes and a quarter note (two eighths tied together) - "Eleanor Rig-", "picks up the rice", "lives in a dre-". So, immediately McCartney has developed a rhythmic theme in his composition.
Also note how a melodic theme is developed in the second phrase. Beginning with "rice in a church", he sets up a melodic and rhythmic pattern which he repeats three times. Each melodic figure, a quarter note followed by two eighth notes, descends down a minor (dorian) scale. The first pattern starts on D, and descends; D to C# to B. The second starts back up one note and descends; C# to B to A. The last figure repeats this theme; it starts back on B and descends; B to A to G. Were McCartney to keep this theme going, the next figure would've been A to G to F#, then G to F# to E, etc.
Now, certainly McCartney wasn't thinking of all this when he penned "Eleanor Rigby". The purpose of this breakdown is to analyze what came naturally to McCartney, so that we can help see what makes his writing so special.
I'd encourage you to look at your own material the same way - does it use a thematic technique? By tweaking your music, could you develop some of your ideas a bit more in this style? These are questions we need to ask ourselves as songwriters.
