Originally Posted by: rockonn91looking into theory, theres a couple different ways of harmonizing.

common harmonies include the root and: 3rd's, 5th's, 6th's, octave.
obviously the easiest to hear and figure out would be the octave. technically, any Diatonic interval can be harmonized with another, but certain ones sound better and work better together. its up to your ear as schmange said.