Okay so I'm not real heavy in theory. I have a basic knowledge and grasp of it due to a semester in college but if I want to harmonize a lead how would I do it.
Depends what kind of harmony you want. One way is to play the same as the lead but 2 scale degrees up, so you'd be playing either a major or minor 3rd depending which degree you're on.
to harmonize in 3rds, you take the note your starting with and play the one three notes away in whatever scale you're using. The starting note counts as the 1st. So the harmony in thirds is basically two notes away in the scale

ex. If you play the 5th fret on the E string, the third harmony would be the 8th fret on the E string

to harmonize in 4ths, you do the same thing but it's the one that is 4 notes away in the scale. So basically you count the note you're playing as the 1st and go three more up in the scale. In standard tuning, this the 4th note is usually the same fret on the string above, depending on the scale your using. It is on fret higher when harmonizing the G and B strings because of that half step difference between notes

ex. If you play the 7th fret on the A string, to harmonize in 4ths you would play the 7th fret on the D string
If you play the 7th fret on the G string, the harmony would be the 8th fret on the B string

To harmonize in 5ths, you play the note that is 5 notes up in the scale from your starting note. Because the starting note counts as the 1st, you move 4 more notes up in the scale. This usually results in a 2 string power chord if you played both notes together, so it is usually play 2 frets higher on the string above. Again there is a difference for when you play the G and B strings.

ex. If you play the 5th fret on the A string, the harmony in 5ths would be the 7th fret on the D string
If you play the 2nd fret on the G string, the harmony would be the 5th fret on the B string

I hope that helped you out a bit

Originally Posted by NAME GOES HERE
Dude, with a name like Cannibal Corpse, what were you expecting? Ponies and rainbows?