Modify isn't the word that leaps to mind when I think of words like Stop, Wait, Pause, Hold on or Hang on. It's the word they chose though, it's our word now too. When you click on the Modify button Revit stops whatever you are doing and puts it in neutral. This button has the advantage of being a one-button-action, click it you are done. Downside? You have to move your cursor to use it, usually quite far from where you are now.
The Escape button is a natural, if you've used AutoCAD at least, some other software too. If you keep your left hand near the keyboard like many do it is easy. Downside? Sometimes you have to tap the button twice to really stop. Why? Some features stay running, assuming you are going to keep using the tool. The first button tap stops what you were doing but leaves the tool running. The second button tap tells Revit you really want to stop.
The Right Click > Cancel option isn't bad but it shares the same issue with Escape, you have to use it twice sometimes. I don't know about you but doing that combination twice right away nevers feels quite right.
Last and probably the most efficient...just start another tool. If you are placing walls and need to start placing doors, just click Doors.
Okay...there IS a fifth way...the keyboard shortcut for Modify, if you have one mapped to Modify.