Arranging a meal...or a song
Perhaps arranging a song is like arranging a meal. What do you want in a well planned meal? It should have unity and variety. If I served mashed potatoes, steamed cauliflower, poached chicken, and bananas, that would not be ideal. It would lack contrast in color, flavor, and texture. However, if I served curried beef, roast chicken, pulled pork, and smoked fish, that would be way too meaty, too much protein, and not balanced with other nutrients. Too little variety is not good, but too much variety can also be bad, as any one flavor may not play well with all the others. However, if I look at my previous fiascos and took the curried beef, added mashed potatoes, served a diced salad with that, and then a slice of fruit pie with a scoop of ice cream for desert, that would be much better. My perfect meal plan is a bowl of soup, a salad, fresh bread, and fruit. A piece of cheese to go with this is not necessary, but good. This kind of formula allows for a lot of variety. One hearty meal can be chili and cornbread with tossed salad and apples and a slice of cheddar cheese. A very different meal could include onion soup with a few slices of baguette, a tomato and mozerrella salad and some grapes.
Ok, now lets think how this may relate to music before I get too hungry. Looking at songs that others have composed or arranged, I observe that each song contains a certain number of elements: enough to be interesting, but never everything and the kitchen sink. This restraint gives an element of unity to a song. For example, a song may have mostly 1-5-8's in the left hand, played together or arpeggiated, plus a few 1-5's thrown in for variety. Another song may use mostly 1-3-5's, but have some broken chords going up, some down, and some taking the bottom note first, then the top, and lastly the middle. Some songs have a section with the melody played an octave higher. Some quick songs have a section of longer notes, giving a feeling of contrast in tempo. I have noticed certain elements in different kinds of music. Just like a specific spice or ingredient can remind me of a regional cuisine, some elements in music remind me of regional music. For example, a melody line with a parellell line running a sixth below makes me think of Hawaii. The Hawaiian arrangements I have also feature 7th chords quite often. Another example is the use of 1-5's in old English music, which gives an open sound that can be ambiguous, because it is neither major nor minor.