Years ago I had a client who was plagued by what she called CHS. That stands for Convenient Horizontal Surfaces. Whenever there was one, she found herself filling it up with something and then had to work to get it free again.
Your desk is a prime candidate for attracting piles, especially when there is empty space on it. It’s a conundrum; you want to have space to work at your desk, yet that empty space inevitably calls out to have paper piled on it.
To maintain your free space, try creating a DMZ for paper. In this demilitarized zone, you make a treaty with yourself not to allow pile attacks. They may occur elsewhere, but this spot is a pile-free zone (PFZ).
It’s helpful to mark your PFZ so you know where it begins and ends and can easily honor your self-created treaty. One way to enforce the PFZ is to use a desk blotter. These come in a variety of materials and sizes. Choose one that allows you enough space to work.
If you can’t find a big enough one, make your own. You could use a rectangle of contact paper or just make a shape with colored tape (it doesn’t have to be a rectangle!). Heck, you can even paint it right onto the desk.
What matters is that you define this spot as the PFZ. Inside the borders: no piles. Outside the borders, piles are allowed. Try to keep them in an in-box if you can.