It may seem simple but the most effective way is to end meetings with a summary of agreed-upon actions, including who is to do what and when. This information should also be recorded in the minutes of the meeting.
Since commitments made after a meeting can slip participants’ minds, you might want to send an e-mail message as a reminder a few days later to communicate to members how important what they agreed to do is. It helps if you establish a norm within the group of "do it the next day"—members should learn over time that they should follow up on their commitments immediately after a meeting.
Tell Me More
If nothing happens, you can call to ask if you can help. This is far more effective than calling to say the individual’s work is overdue. The offer to help is likely to be turned down, but it should energize the participant to do as promised.
Still no luck? Shame the individual for his or her failure to follow through by including on the agenda for each meeting a status report of all actions agreed to at the previous meeting. No one wants to be reminded in public about what they haven’t done.