This Slash solo is really basic blues shapes, with a few other notes thrown in here and there. So you're lucky -- this material is not tricky harmonically. You don't need to learn much theory.
To get to this level, just take a metronome, set it very slow, and go up and down your pentatonic shapes. Strengthen your fretting hand by trying to do it all with hammer-ons and pull-offs. Then, all you do is increase the metronome by one click, then another click. Take it from very slow to faster and faster.
When I was in high school, I used to sit for hours and hours on my mom's couch, watching music videos on MTV and just letting my left hand go all over the place in the shapes. You couldn't get the guitar out of my hands. It would get to where I was not consciously thinking about playing at all. I taught my subconscious how to play guitar. It's just forming a habit, getting your muscle-memory established, and hitting as many notes as you can up and down the neck. I'd sit and think about something else completely and just keep that left hand going. I'd do trills, bends, vibrato all day long, not even thinking about it.
Of course, you should always focus on what you are doing at first -- make sure you are setting yourself up properly, have good posture, et cetera. But once you've told your hands what to do, just let them go at it for a while. Correct them when they need it.
Most of the time when you see these guitar gods playing what seems like something really difficult, they are probably daydreaming about something else and just making sounds out of habit. They do make it look hard to do because it's a show, but guys like Slash could be reading a novel while doing all that stuff. Besides, the last thing you want to be doing is really having to think about what you are doing when you're playing to 10,000 people.
Just realize that if you play something very slow, at a level that is totally comfortable to you, that is what it is like for Slash to do all of his stuff. All you have to do is keep increasing your speed on those blues scales. It takes discipline and patience to push that comfort zone. You'll get a little faster every day, just build up those muscles and speed like any other sport.
To me, the beauty in Slash's playing has always been his composed guitar leads in his songs. That is what takes maturity beyond just getting your hands working correctly. And please remember that you are not necessarily making good music just because your hands can move fast. Just like running fast, you have to look where you are going.
-Carl.
Carl King[br]GuitarTricks Video Director / Producer
