How to write a good harem?

[BearlyAlive]

Avoid the mistakes most writers tend to make:
Write real characters instead of trophies
Let them interact with each other outside of MC and on themes that aren't MC
They need different goals and motivations, bonus points if some of them conflict
Let them act outside the flock, alone or in smaller groups
Give them the spotlight or even better some POVs without MC around
Make their goals and ambitions not completely interlinked with MCs progression

Best way to solve this is making every "trophy" an MC of their own story line and have them occassionally intertwine and/or conflict with your Main MC.
Nobody likes an OP harem MC that instantly solves all problems of everyone ever existing with their magical smartphone or some other McGuffin.