Monday morning meetings from my investment banking days could have been taken from a textbook on how not to hold a meeting. Firm-wide, hours-long, and vastly time-inefficient, I used to get through those meetings by pretending I was watching a live taping on Saturday Night Live (I kid you not, one meeting featured a screening of the firm's new "motivational video," which depicted old white bankers dressed as hip-hop artists, rapping about the stock market).

Sitting around those conference tables, I couldn't help but think: just how much is this meeting costing the firm? Take everyone's salaries, calculate the hourly rate for their work, multiply by x hours on a weekly basis--staggering.

I believe there is a time and a place for a Monday meeting, which can be an important tool for creating strong company culture. But always ask yourself: what is the literal cost of my time? What is the cost of my employees' time? If you do need to hold a meeting, make sure you're using that time to create real value.

Keep people (literally) on their toes

Research on attention spans tells us that the average amount of time people can pay attention before starting to zone out ranges between ten and twenty minutes. That's in part why the ever-popular TED talks are capped at eighteen minutes in length. So keep it brief, keep it moving, and keep people standing.

A great general rule is that people should be able to stay on their feet throughout the entire meeting. If it's too long to stand comfortably the whole time, then it's too long, period. Work expands to fit the amount of time that you give it. So if you give a ten-minute meeting one hour, it will become a one-hour meeting. There's a reason that the expression is "short and sweet."

Take the first minute to say what you're going to say

Do this for the meeting as a whole, as well as for the specific topics you plan to cover. First, answer the question: what is the purpose of this meeting, in five words or less? Then, let your listeners know what you'll cover, in what order, and how long each item on the agenda will take. If necessary, bring everyone up to speed, very briefly, on relevant topics so the whole team starts on the same page.

When people know what to expect, they will engage more effectively. Having a deadline for a given topic helps spur ideas and dialog. When people know what they'll be discussing and that they have ten minutes to discuss it, they are more focused and more driven to get to the point.

Give a firm end

Declare the time frame of the meeting and then, no matter what, call a hard stop. Of course, you can tailor the length of your meeting accordingly; a strategy planning meeting will take longer than a project status update. But don't let any meeting drag on. A long-winded meeting simply dwindles in effectiveness every minute it stretches on.

If the topic merits more discussion than you anticipated, schedule appropriate follow-ups. You can't solve the world in the span of one meeting. It's okay--even preferable--to leave people curious, interested, and wanting more.