Timesignal is right, those tracks are not very hard to play once you know the basics. I'm no expert so my only advice is not to listen to other guitarists too much, otherwise you won't be able to get your own style. Other musicians can give you a great sense of what you can do when you put all of the pieces together to make nice progressions and licks eg alternate picking, phrasing, arpeggios, tapping and all of the other lead techniques. But I think its most important to just play without trying to sound like anyone else. That's why i never play other peoples music. I never practice scales and I don't know the names of most of the notes on the fretboard. However, I can play piano and can understand music theory on that instrument. I think that helps give a different perspective sometimes.
The way I write lead is pretty simple, I write a backing track, then imagine the lead in sections before I even lift my guitar up. Your mind can play solos a hell of a lot better than your hands can (unless you are a true virtuoso like Vai). I fiind that I play shapes and progressions that I would never normally jam when I imagine the music first. It helps me to stay away from playing up and down scaley solos. As far as speed goes, that's something you will achieve more quickly when you're playing your own music because you are not trying to bend yourself to someone else's technique. At least that is what works for me. Best of luck, if you record anything post it in the Listening Post and I'll check it out!