Productivity-wise, one of the trickiest areas to track is the “Waiting For” category, which contains all the stuff you’re waiting for other people to accomplish. Thank goodness for David Allen, productivity expert and author of “Getting Things Done,” who taught me his low-tech but elegant way of tracking “Waiting For” items back in 1998. I’ve been using Allen’s  simple method ever since, and it has saved my sanity countless times.

To employ Allen’s model, you will need to label a physical “Waiting For” folder, either on your desk or in the front of your closest file drawer. You must also create a “Waiting For” folder in your email in box.

When you come across a piece of paper that requires no action on your part but does have an incomplete element that you are waiting for someone else to handle, file it in the “Waiting For” folder. You will be getting in and out of this folder a lot, so consider purchasing a plastic file folder instead of using the traditional manila.

Examples of items that would go into this folder are:

• Receipts from items you’ve mailed or shipped that haven’t been received (by someone else) yet

• A receipt or credit slip that you are waiting to reconcile with your credit card statement

• Invoices you’ve billed that haven’t been paid

• Anything you’ve delegated that is unfinished

• Travel arrangements that haven’t been confirmed

Use a highlighter to mark a specific issue or make notes on each paper so that you can be easily reminded of what you are waiting for and be able to ascertain quickly whether or not it’s been handled so that you may file, recycle or shred the corresponding paper. Alternatively, if an issue has not been handled, you would then decide whether or not to make a phone call or otherwise follow up to check on the status. Be sure to then make a new note outlining any updated information.

The basic underlying principle to Allen’s “Getting Things Done” methodology is to get things out of your head and into a trusted system. When you stop relying on your memory to keep your projects moving forward, you will be amazed at how relaxed and efficient you can become. That’s why if you’re waiting for something that does not have a piece of paper associated with it, write yourself a note and stick it in the folder. For example, if you lent something out and are waiting for it to be returned, you would write, “Blue Prada sandals to sister, 4-25-14” or “Mad Men DVDs to Heather, 5-1-14,” and hope that you’ll see them again someday.

The “Waiting For” folder in the email in box is incredibly useful. With back and forth emails it is difficult to know who’s got the ball on various tasks and projects. When you’ve passed the ball to someone and are now “waiting for” an action or response, you can simply drag the last email in the thread into the “Waiting For” folder where it will remain until the person has answered the question, completed the task, or thrown the ball back to you.

I’m constantly using my “Waiting For” email folder for shipping confirmations on Internet items. When I order an item and get a confirmation email, I drag that email to my “Waiting For” folder. After I receive the item, I can delete the various emails associated with it. Basically, instead of clogging up your inbox with these bits of unfinished business, you will be corralling them all together in one folder — everything you are waiting for at a glance.

It is one thing to keep reminders of things you are waiting for in a file or email folder, but it won’t do you any good at all unless you review these folders on a regular basis — at least weekly. Then you can make decisions about whether you need to pick up the phone or send an email to check on something or if you can let it sit in “Waiting For” a little bit longer.