What is the best approach to address conflict in meetings?

Everyone has to freely place their ideas and the meeting leader should peacefully pick the best idea.

( if it's a problem of idea )

Personally I believe the best approach to address conflict in meetings professionally is to state the negative, problem, or the conflicts first and be as honest as possible then state the positive about that problem afterwards and how you can improve the negative. Adressing a conflict this way can let people know you're aware of both negative and positive sides and you're not only focusing on the negative but that you just observe both sides.

If you state the positive after the negative the positive is more likely to be highlighted in their ears.

As an example...

"I wasn't necessarily fond of the idea about the specific flower design for the cake, although I do love that idea about using flowers, we can try changing the color of the flower to match the cake? but keep your design?"

If there's still a conflict, try asking the person why they chose that decision? be as open minded as possible and listen. It's perfectly okay if you still have a different option if this is so say you understand what they're going with and try suggesting something you can both agree on using both of your opinions.

Thus you will all be happy.

Hope this makes sense or helped.