Mixing is an entire science. And like in each science, you could have sensible expertise and theory. Practice is an important factor in all learnings, however with out idea it is going to be extra complicated. Mixing is not only a soundproducing process. It involves understanding of how instruments sounding, how they need to sound and other completely different things. For rookies it's all the time a troublesome to combine music in a correct and quality level. However with practice it all begins to come together and make process extra snug and even. Learn more about mixing in my article - How to mix a song - important things