Once you've made your masterpieces or great songs, you will want more people to listen to your music. Then where to start?
Demos can be a great way to get your music heard. You can also read a lot of books ebooks, blogs and watch a 100 different youtube videos and lose your mind and your sense of direction.
For beginners, you could check out musiciansempowered.com for useful http://www.musiciansempowered.com/blog/music-industry-marketing-strategies-on-selling-music tips and Music Industry marketing Strategies on Selling Music.