Years ago, I decided I wanted to play the guitar. Keen and eager, I rushed out and bought a guitar, amplifier, effects pedals and a few books. I got it all home, plugged it all in and then made a noise that sounded like a herd of cats all caterwauling out of tune.
After some days and weeks of struggling and irritating my family I decided that I needed to learn properly. The best way to learn properly is to get someone who is already an expert to teach you.
So I went out, found someone who was an expert guitarist in the style I wanted to learn and studied with them. I also watched my favourite guitarists playing; watching exactly how they played and moved their hands. I, of course, copied them (though I now realise its called modelling!).
With an expert teaching me, I soon became much better at the guitar and was no longer banished from the house when I wanted to play.
I could probably have taught myself guitar from books and from fiddling with the guitar, but it would have taken me a lot longer than it otherwise did. Through using a mentor, I sped up the learning process and avoided a lot of the pitfalls, bad habits and mistakes many self taught...