Most people usually have a general idea of what music style they want their song to be. To go even further, most people have a favorite style of music and tend to gravitate towards that style with most of their songs.
As it is with song structure, the style needs to reinforce the message of the song. For example, romantic songs usually sound soft and delicate, because that style is designed to produce tender and heartfelt emotions. On the other hand, a song about a controversial political issue might be better represented by a heavy rock style instead of a soothing ballad. Music, even without lyrics, is a form of communication. Certain styles of music produce certain emotions inside an individual. This mysterious fact epitomizes the sheer power that music possesses. So make sure that the style of music you choose lines up with the emotions that you want to invoke within the listener.
There is something else that needs to be discussed while we are on the subject of song style. Whatever style you choose, make sure you incorporate effective dynamics. What are dynamics? In the musical sense, dynamics have to do with the variation of volume in music. Tempo (speed) can also tie in with dynamics, as the tempo can sometimes signal the loudness or softness of the volume in a song.
It is critical in effective songwriting to implement a moderation of change within the song. If a band plays at the same volume through an entire song, odds are that the listener will lose interest and get bored, or even worse…annoyed. Think about it in terms of a movie. If the whole hour and a half is full of non-stop action sequences without having at least one quieter scene with dialogue, then that is going to guarantee most viewers an hour and a half long headache. Granted, some people wouldn’t mind this type of movie, just as some people might not mind a song with monotony, but most people would be turned off. Most songs have some sort of breakdown, where there is a temporary detour from the overall volume and tempo of the rest of the song. Creativity doesn’t produce a song that sounds the same the whole way through. So if you want to keep listeners interested, give them a balanced dosage of change in your song.