Yup, as Neal says in the video, sustain, vibrato and timing are all very important.

The rest is chord tones, chord tones, chord tones :).

This means you have to know what chords you are playing your solo over, and target notes from those chords. If you know your arpeggios in a few different positions, this isn't too hard.

For example, if you're playing over the chords G, D, C, C - the scale of choice would probably be the G major scale (same notes as Em). The easy way would be to noodle around in the E minor pentatonic scale.

But, if you really want to sound good (like Slash for example), you would use the E minor pentatonic scale (or E natural minor/G major) as a base, or shell, and land on and target notes that are in each chord.

Start by learning the E natural minor scale in the 12th position. Then figure out where the G major, the D major, and the C major arpeggios are in that same position. Those are the notes to target over each one of the chords. You can use the rest of the notes in the scale as passing notes, but really accent the chord tones.

Hope this makes sense. /Ben