Nobody wants to be deemed a nag, but sometimes you have to let your inner-nag come out to push people to act or move tasks along. Just make sure you follow this advice:
Turn to technology. Schedule tasks and deadlines in a shared electronic calendar and through email to provide recipients with automatic reminders. Doing so eliminates your need to keep reminding them.
Let them know that you won’t remind them forever. If you have mentioned it multiple times and they haven’t made progress, say “This is my last reminder. If [the task/action] isn’t done by [deadline], I’m going to [course of action].” Most people will be motivated to act, especially if their inaction negatively affects them.
Don’t let your irritation show. You may think you have to be rude to some people before they’ll respond, but that gets you nowhere. Be respectful and polite when you talk to them about missed deadlines, stalled progress or other issues.
Ask the right questions. Saying “Why isn’t this done yet?” or “How can you not be finished?” puts people on the defensive. Instead, ask “How are you progressing on …?” or “What is the status on …?” From there you can talk about what they can do to move more quickly.
Be reasonable. Bombarding co-workers with several messages in a few hours borders on harassment. If the issue is urgent, convey that to people. However, offer them time to respond.
— Adapted from “Six Ways to Nag Without Seeming to: How to Make Sure Your Work Process Keeps Flowing,” Laura Stack, www.theproductivitypro.com.