Help in harmonizing melodies

Write out the notes of the melody you are singing. Find out which key it is in. This will give you an idea of which chords to use. Your melody will have important notes (typically longer notes on which the melody will "rest") and less important notes (shorter notes in between or leading up to important notes). Chord changes often happen on the important notes, but not all important notes imply a chord change. Confused? Let's try an example. Suppose this is your melody:

|-------|-------|-------|-------|
c d e f g a b a f g a g c


This is clearly in C major, it has all the notes of C major, and it starts and ends on the C notes. There are various ways you could add chords to that, here's a very obvious one:

C G F C
|-------|-------|-------|-------|
c d e f g a b a f g a g c


That one uses all the major chords of the C major key. Each important melody note is also the root note of the chord. If you want to add some minors into the mix, the following might be a possibility:

C Am Em Dm C
|-------|-------|-------|-------|
c d e f g a b a f g a g c


Of course, there are many more tricks you can apply, using suspended chords, augmented chords, seventh chords, or using borrowed chords, etc, but these will give you something to start with.

Good luck!

Thanks a lot Zaiqa!!!

I thought nobody would reply this question!
Very informative!

Cheers
Roberto