The significance of the theme should indicate the nature of the accompaniment. To take a simple sentiment and overload it with a modern complex harmonic accompaniment is like going after sparrows with a sixteen inch siege gun.
Comedy in the song should not be associated with tragedy in the accompaniment. A lively poem should not have a lazy accompaniment. The great songwriters were models in this respect. This accounts for their greatness. Take for example Schubert's _Wohin_ and _Der Wanderer_, Schumann's _Der Nussbaum_, Brahms' _Feldeinsamkeit_. These accompaniments are as full of mood as either poem or melody.
The element of proportion enters into songwriting no less than into architecture. A house fifteen by twenty feet with a tower sixty feet high and a veranda thirty feet wide would be out of proportion. A song with sixty-four measures of introduction and sixteen measures for the voice would be out of proportion. Making a song is similar to painting a landscape. In the painting the grass, flowers, shrubbery etc., are in the foreground, then come the hills and if there be a mountain range it is in the background. If the mountain range were in the foreground it would obscure everything else. So in making a song. If it tells a story and reaches a climax the climax should come near the end of the song. When the singer has carried his audience with him up to a great emotional height then all it needs is to be brought back safely and quickly to earth and left there.
I have mentioned the principles of song construction, but there are other things which have to do with making a song effective. One of the most important of these is association. Let us remember that the effect and consequent value of music depends upon the class of emotions it awakens rather than upon the technical skill of the composer, and that these emotions are dependent to a considerable extent upon association. We all remember the time honored expedient of tying a string around a finger when a certain thing is to be remembered. The perception of the digital decoration recalls the reason for it and thus the incident is carried to a successful conclusion. In like manner feelings become associated with ideas. Church bells arouse feelings of reverence and devotion. To many of us a brass band awakens pleasant memories of circus day. _Scots Wha Hae_ fills the Scotchman with love for his native heather. The odor of certain flowers is offensive because we associate it with a sad occasion. The beauty of a waltz is due not only to its composition but also to our having danced to it under particularly pleasant circumstances.