In principle, groups are apt to be most peaceful, most efficient, and make their best decisions when one-on-one conversations happen easily and often outside of group settings. Especially in the age of email it is tempting to make every conversation a group conversation, but group conversations by e-mail are often inefficient and cause conflict. If I have a question for a group member or a comment about a group member's behavior, it is usually best for the group if I talk with that person one-on-one.
In a one-on-one conversation it is easier to ask and answer direct questions, be honest, and find commonalities. One-on-one conversations build trust and shared understanding, cornerstones of good group decisions.
Practical Tip: Muster up the courage to talk one-on-one. Start with a question. Have an open mind. Seek first to understand.
If you want to show everyone how smart you are or want to publicly surprise your enemies to get the upper hand, save all your questions and comments for group settings. If you want your group to make the best possible decisions with the least amount of conflict, work quietly behind the scenes one-on-one.
Of course it's okay to ask questions and make comments in group meetings or by group email. But especially if you sense conflict coming, try one-on-one first.