Sometimes face ti face can be good, but I often prefer email, for the reason that everything gets documented.
A previous line manager of mine would never document anything, and his standard response was "I thought we talked about that". Sure we did, but you changed your mind then changed it again, then again after that. I can't remember what the final outcome was.
1. Start by setting the agenda, and critically, the desired outcome. "At the end of this meeting I want to have a decision on X, or a date for when we can make that decision."
2. Have your meeting. Minimize attendance. 3 is perfect. 5 is okay. 7 is pushing it. Have a very clear moderator/leader for the discussion.
2b. Moderator/leaders should be hard-asses about forcing tangential discussions offline/into a parking lot. This is probably their most important function.
3. At the end of the meeting, the leader summarizes the outcome to all participants. This is a critical step. "So, Joe, you will come back to me on Friday with a decision on X. Phil, you'll be working with Joe to pull that answer together."
4. Write the meeting notes down in a permanent place. Email is too ephemeral. A document management system of some kind with an email notification is ideal. Record actions for those who have them, with associated dates.
Stakeholders should also follow-up on actions with due dates to make sure they're closed out. This can feel like nagging/cat herding, but it's vital.
The reality is, many decisions/discussions are too complex to do over email, particularly if the number of stakeholders grows beyond 3. There's far too much room for confusion/ambiguity and a lack of ownership on follow-up actions. Mix in the ease with which emotional components can be lost or mis-interpreted over email, and my tendency is to push for a voice or in-person discussion the minute an email thread goes on for more than a day.
You need a dedicated person to take meeting minutes, ideally someone who isn't otherwise part of the meeting because humans are bad at multitasking. I especially find it hard to take notes and focus on the meeting (nevermind actually contributing).
A previous line manager of mine would never document anything, and his standard response was "I thought we talked about that". Sure we did, but you changed your mind then changed it again, then again after that. I can't remember what the final outcome was.