Repetition and variation
OK so how do we keep things flowing if we can't think of anything? One method of course is simple repetition. It's an essential ingredient of most music. So many beginners are scared stiff to repeat an idea, afraid that it will be boring to do so. On the contrary, an opening phrase will often set an air of expectancy. When this phrase is repeated, the listener's subconscious picks up on it and a basic psychological and emotional sense of musical fulfillment is achieved. Of course it would be utterly boring if the same phrase were repeated endlessly. This is why we also need variation. Repetition and variation, hand in hand together they make a very powerful composition tool for almost any style of music.
