A problem is that you don't really know if what you are doing is working, unless it isn't because you have a failure. Maybe I have never been pickpocketed because my system is secure and maybe because no one has tried.
I think the important thing is to have a system. I can get distracted, flustered, careless....unless my behavior is part of a habit stack. This is when one action automatically leads to another leading to another through to a completion. If I have to think of where my credit card is before I use it and where it goes after I use it, who knows what will happen. Instead of thinking and behaving carefully, I do it the same way each time. This takes no effort once the series is established.
I use a Tom Bihn medium sized cafe bag. My passport is in a case and the case is in the zippered compartment at the front of the bag that is under the flap. I always secure the flap with the clip provided. Always. No thinking. The zipper pull is secured by a large safety pin to the bag. To get to my passport, a thief would have to get under the flap, unpin the zipper, unzip the zipper and reach into the pocket. Not impossible, but not easy.
For money and cards I have 2 Tom Bihn clear organizer pouches. One has one zipper and is smaller, the other has 2 sections each with a zipper and is larger. They have clips on them and they clip to the inside of my bag. I can have my pouch out of my bag, but it stays attached. I can't set it down somewhere and forget it, it is attached and would follow me! Again, not impossible to get inside my bag and unclip one of these, but not that easy either.
I never leave CC, passport, or cash in my hotel room. Have my stuff that I need for any situation.