Watch the David Gilmour online guitar lesson by Jeff McErlain from Kings of Tone
If you plan on learning some of David Gilmour's solos, which I suggest you do, focus on one. Take one of his simpler solos like "Mother" from The Wall. Really listen closely to his phrasing, vibrato, bends, and try to emulate it as closely as possible. Many of my students will learn bits and pieces of a solo and nerve the whole thing, sometimes that's not a bad thing but in this case learn the whole solo. What you learn from one of Gilmour's solos will help inform all the others you may want to learn. Play along with the recording! I am also amazed when students will learn the solo but not play along with the recording. That's the point, to try to make it sound as close to the recording as possible.