The secret to melody is all about building a song as you go along. Think 
of a song as a mountain, you start at the bottom and your objective
is to take the listener to the peak. Melody is an important tool you use 
for this.

The first verse starts at the bottom of the mountain, the last half of the 
first verse is getting to the middle of the mountain, then your chorus is 
the peak, the heightened memorable, melodically catchy, unforgettable part 
of the song. Shania Twain may not be the most dynamic lyric writer in the 
world but when it comes to great melodies she really knows how to put something 
on a record that will stick in your head and have you humming it all day.

Let me stress how important it is to have a melodically strong chorus,
a strong melody in the chorus can turn simple words to a powerful 
statement. Lonestar's "Not A Day Goes By" is a good example of simple 
chorus lyrics that come across as powerful because of the melody.
"Not a day goes by that I don't think of you, after all this time
you're still with me it's true". Those lyrics alone are really simple
and not too exciting, but add a power melody to them and there you go,
a hit song.

A great example of how a song builds up is "Breathe" by Faith Hill, it
starts out really slow, sultry, with her singing very low notes, the 
second verse gets a little more instruments going providing the leading 
up to the climax which is the chorus. A great song leads you along 
building and building where your ear just can't wait for that power chorus 
to finish it off.

Chord structure is not the only thing that will make a chorus powerful,
I have found that many choruses are sang higher than the rest of the song.
A good example of a song that has basically almost the same progression 
through the entire song is "Concrete Angel" by Martina McBride. The chord
progressions are all the same in the verses and the chorus except for the
last two lines (of the chorus) but what ma