So basically, I have 2 idiot-proof approaches.
Approach 1, step 1: Set the camera to f/16 and 1/125s on a bright (or even slightly overcast) day, depending on your film ISO.
Approach 1, step 2: adjust my 35mm lens such that the DOF scale allows for a distance of between 1.2m to infinity to be in focus.
Approach 1, step 3: walk around and allow serendipity to do its work.
Approach 2, step 1: focus on a brick wall.
Approach 2, step 2: fumble with camera.
Approach 2, step 3: allow serendipity to do its work.
Camera: Leica M6
Lens: Voigtlander Nokton Classic 35mm f/1.4 SC
Film: Ilford XP2 400