These are just things that I thought could be improved upon through observations. I'm not a music major so I won't be using official terminologies, take what I'm about to say with a pinch of salt

Duets are very different from solo, it's the chemistry between singers that can create works of bang. The most obvious advantage of a duet is that you can have 2 voices instead of 1! Think about these just to name a few:

"Sing-along"

This is gotta be the most common scenario in a karaoke box. 2 singers singing the same tune, at the same time, competing to see who's voice is louder after a beer (lol)

The downside is that it sounds very obvious if 1 singer is out of tune/tempo (even slightly) and quite frankly, it's boring! Try to minimize "sing-alongs" and try to mix in other techniques.

"Rally/Tag"

This is where each person takes turn to sing a section of the song (eg Nichijou) and should be relatively easy to master. Make sure each singer is on pitch and sing with clear voice (since no one can cover for you), this should take care of the bulk of the duet.

"Effects"

This ain't the digital sound effects that you're thinking about lol

I'm referring to when 1 person sings while the other makes random "sound" to decorate the section. Just make sure that the main singer's voice is clear and on pitch so that the "effects" doesn't kill it.

"Harmony"

This usually means 1 person singing the main chord while the other sings at a few keys lower. Yes, very common technique but very awkward when one jumps in to do it, try experimenting a little!

Harmonies are "big guns" that one can use to deliver heavy punches, use it for the climax! It'll run out of steam when overused.


^ Try mixing in those techniques in your next recording and see if it sounds more dynamic than usual. If you're looking for simple examples, check out COOL&CREATE's songs. I'll leave one example here, this has all the techniques we touched upon (and it's a nice song hue) (https://osu.ppy.sh/b/40212):