The bridge can really make or break a song. A well-written bridge will draw the listener in with something fresh and interesting.
But so many people struggle to come up with new ideas for the bridge. (Especially when you've already written two verses and a chorus - is there even anything left to say?!)
I find it helps to keep in mind the purpose of the bridge: to introduce contrasting material. To do or say something different than what's already happened in the song.
Here are some ideas for creating contrast your bridge using different aspects of the song: the lyrics, the accompaniment, the chord progression, and the melody.
Lyric Contrast: Pacing
Think about the lyric pacing in the beginning of your song - are you singing fast-paced rhythms or more sustained notes?
Now do the opposite in the bridge!
Lyric Contrast: Repetition
Is your chorus really repetitive (think both melodically and lyrically)? Switch things up by using less repetition in the bridge.
Or do the opposite: I have a tendency to write less repetitive choruses, and then contrast it with a repeating one-line bridge.
Lyric Contrast: Plot Twist
Think about your actual lyric content: Is there a way you could surprise listeners with a plot twist in your bridge or explain the situation in a different way?
Accompaniment: Timbre
There are tons of ways you can switch up the timbre in the bridge - Try introducing a different drumbeat, new instruments, or additional vocal harmonies.
Or try a more stripped-down bridge, with only one or a few instruments.
Chord Progression: Pacing
Think about how fast your chord progression changes are throughout the song - Do you hold each chord for two beats? four beats? eight beats? Now try faster (or slower) paced chords in the bridge and see if you like it!
If you do prefer to keep the chord length the same, try changing up your strumming pattern.
Chord Progression: Non-Diatonic chords
Try introducing a non-diatonic chord (a chord outside of your key) in the bridge - these chords tend to stand out and really grab the listener's attention.
Tip: You don't want the chord to stand out TOO much, so choose carefully ;)
Melody: Vocal Range
If you've used the lower part of your vocal range throughout the song, try centering your bridge around the higher part of your range. (Or vise versa!)
Melody: Layering/Harmony
Add in (or take away) some vocal harmonies in your bridge. If you want to get really fancy, try layering several melodies on top of each other, adding in each melody one at a time, building to a climax.
I hope this helps spark some ideas for your next bridge! Remember, you don't need to use ALL these strategies (that would just be ridiculous!), but just one or two of these techniques will help your bridge stand out.