One vital technique to add more melody and emotion to your playing is by bending the string up to a certain pitch, half-step, whole step, one and a half steps, 2 steps etc...

Although bending won't make you shred any faster, if your solo has no emotion or melody to it people probably won't enjoy it - it's what sets apart the great from the good

To do this simply insert your finger on a fret and bend upwards or downwards (Whichever you find most comfortable). One thing you must make sure is that the note you bend up to is in key with the actual song. To get a rough idea of how big each bend should be, practise bending and then actually play the fret you are trying to bend up to.

Also, another vital technique to use while bending, always have another finger placed before the fretting finger, this will make the string easier to bend, especially if on a lower fret. Another cool technique to add more feeling into your bends is a rake, to rake simply mute the other strings you are descending from (that's if you're looking down) with the palm of your hand, scrape across the muted strings and hit the string you want to bend, this will create a nice effect used well by such players as Ritchie Sambora and Eric Clapton. For big bends check out some Pink Floyd also, particularly the 2 and 2 1/2 step bends in the solo to 'Another Brick in The Wall Pt.2'.