To start, determine the musical direction belongs to the composition. Directions in music is global, diverse and include a variety of styles. As example, areas such as pop, rock, folk, jazz music, classical, disco, hip-hop, reggae.
Take, for example, rock music. It is divided into alternative, hard rock, metal, etc.; the metal, in turn, is divided into many styles. Electronic music includes styles of Electro, house, Trance, Techno, Drum and bass, Industrial and many others. To define the different styles of music, you have to listen interesting direction to understand it.In fact, musical styles so much that they know is simply impossible. Besides, there are always new and new styles, usually at the junction of the existing ones. Sometimes it is difficult to refer a contractor to a specific style, because today musicians love to experiment. Often performers come up with a new style, because it does not adhere to any existing genre.
Work out in the definition of music styles. Take any song and try to describe her character: what tools are used, what rhythm, melody, and manner of the vocals (if any), the content of the text, what impression composition, your subjective emotions. Then try to remember one or a few songs that seem similar to this. They probably belong to the same style. Do this with the musical work of another genre. Soon you will be able to do it with ease.
Ready and full list of musical styles you hardly will find somewhere. The surest way to learn to identify them is to listen to different music. Then any work you will be able to give you my definition, even if such thing does not exist yet. The style need to feel, because music is art, this is its difference from the exact Sciences, where everything is laid out on the shelves.