Your calendar and a pending file are just the ticket. Make a note on the calendar to remind you of the thing to do and keep the corresponding paperwork in the pending file. If items have an assigned home, they will gravitate toward it. If they have no assigned home, they will wander into aimless piles on your desk. Decide how you might use an Item in the future, create a place for it, and put it there.
Incoming information is the enemy.
Don't ignore it or put it off. Have a station for dealing with all forms of incoming data mail, e-mail, faxes, phone messages. Have your calendar handy, your to-do list and a huge trash can. Write appropriate notes in your calendar and toss the supporting documentation, unless it will be needed. Don't keep anything you can find somewhere else.