There are expensive tools available to trace wires in walls but probably not what you want this little project.
First do this, find all GFCI outlets and make sure they are not tripped. If the switched circuit has a GFCI outlet that is tripped you may find nothing works on the circuit which gets confusing when operating the wall switch.
Second, make sure there is power to the switch. It may not even be connected to anything.
Third, make sure you have good bulbs in the ceiling lights and wall sconces. The bulb may be broken.
Finally, with the switch off, try plugging several lights and radios into several outlets in a single room then activate the switch. Check to see if any of the lights that were on are now off or off and now on. If the radio turns on then that will tell you the switch outlet combination. Repeat until all outlets are tested.
I had a switch that did nothing on an old house I was rehabbing. It was near the front door so I thought it was a porch light or hallway light. A couple months later, I finished rehabbing a bathroom and reconnected power for that room. That's when I found the switch controlled a single outside wall outlet that was on the same circuit as the bathroom wall GFCI outlet. The rooms were 30 feet apart and had no logical connection. You just never know what people are thinking when they add an outlet.
