BRIDGING THE GAP
A Bridge (sometimes called a middle 8) is usually found after a second chorus, certainly later on in a song. It's an opportunity to bring a new perspective on the same subject.
Think of it literally that way. When you cross over a real life bridge, you still have a similar view but the angle you see it from is different. Maybe you can see something closer up that was too far away before.
The Bridge in a song should do the exact same. Offer a fresh outlook on the Chorus and the main theme of the song. It can have a totally different rhyme scheme, length to other sections and even be a topic that is connected but perhaps a little tangential to the main theme.
Another way to change things in the Bridge is to add a twist to the song story. So that when you next hear the Chorus you realise it now could mean something entirely different.
But don't stay too long in this new viewpoint, cross back to a familiar Chorus or Pre Chorus straight after, so the listener gets back to familiar ground.
If you are enjoying this series, please contact me and let me know, and if you are struggling to apply these ideas to your own writing I'd be more than happy to help.