There are few people in the world that can pick up a skill immediately and become a master without taking the time to practice. We generally consider these people to be geniuses or prodigies. For the rest of us, mastering a new skill takes a lot of time and a lot of effort. It also takes a lot of dedication because sometimes the time lag between starting and becoming proficient can seem entirely too long.
When it comes to learning how to play a musical instrument, practice is unbelievably vital. There is very little chance that the first time you pick up a cello or sit at a piano that you will be able to make a sound that even resembles music. But with a little time and effort, and the right instruction, you soon find that your practicing has paid off. This is true whether you play a classical instrument or want to learn guitar.
There is an old adage in the music community that you play the way that you practice. Essentially, this truism means that if you are lazy and sloppy when you practice then you will look lazy and sloppy when you perform. Regardless of what instrument you are trying to master, you need to practice effectively and actively. That is why...