It's a challenge to keep track of everything you must discuss with co-workers involved in a project. Project folders are a good start, but each folder contains issues involving various people. You may have 4 issues, in 4 different project folders, to discuss with Sue. How can you remember them all when Sue phones?
A commonly-used method that doesn't work is to remove all papers to be discussed with Sue from their project folders, and put them in a pile - when Sue calls, you go through the pile. But this causes problems later because you don't have time to put the papers back in the folder.
The solution -- Use colored flags or sticky notes to 'sort' paper without removing it from its project folder. Use visual cues. If Sue's last name is Green, she gets the green flags. When you see a paper to be discussed with Sue, stick on a green flag. When Sue calls, reach for the green-flagged papers. (Remove the colored flag when you're done.) How about Bob, your co-worker who's always down in the dumps? Assign him blue tabs. (I don't recommend you tell people the reasons for your color choices!)
The benefits are many: You don't have to call Sue again because you forgot to ask her something. You spend less time moving paper around. And you won't misplace things.