Okay, so you have some really good stuff going here. In song structure, especially in a song like this, you need to have a sense of how the song is going to "build up". So the beginning that you have is nice. It's very good for the intro. Think about it this way:
1. Intro
2. 1st verse
3. bridge(which is kind of a transition to the chorus)
4. Chorus- This is where the song should be the strongest. This is where you have the catchy melodies.
5. bridge (which is toning down the chorus to transition to the 2nd verse)-
6. verse 2
7. bridge and so and so forth.

My explanation most likely sucks, and song structure really depends on the type of song. But it all follow a pattern really. Good luck!