Timeboxing is important. By limiting the amount of time we take for meetings or tasks we invite ourselves to focus on value. We also learn from when we go over time.
Meetings are not stupid, but it's easy to do wrong. It's easy to dive into details, or trying to get everyone to agree. I love to joke around and spend a comfortable and joyful time together, but it's really not my time to spend. It's Procurios' and the customer's time.
Timeboxing helps us to keep an eye on value. It's an art! Don't fall into the trap of scheduling by the hour, or even half hour. Schedule exactly what you think you need. If you need 40 minutes then meet 40 minutes, not an hour. Tasks and meetings have a tendency to expand to the allotted time.
Make sure an alarm is present and clearly visible. We use Time Timers but anything that visually counts down is fine. I use it for my pomodoro sessions as well. Have an agenda and make sure everyone knows what they can expect and what is requested of them. Customers for whom timeboxing is new may feel uneasy the first time, so make sure they're comfortable.
Make sure to remind eachother periodically how much time is left. And when we are still talking about valuable things when we're out of time, then we'll know that for the next meeting we maybe need to reserve a bit more time.