Practice. Or... How to shoot by instinct. With your eyes closed, try adjusting from one aperture to another (e.g. f/2 to f/5.6) by feel and sound. You need to know where you're starting from and how many clicks per stop (ZM lenses have thirds, Leica and Voigtländer have halves). Check and see if you're right. Do the same with the shutter speed dial. Once you're confident, try changing from one exposure to another using both controls. You can even do this with focus distance on lenses equipped with tabs, nub or levers. Or with the manual mode metering. Before you know it, you'll be able to control the camera quickly and precisely, even in the dark or down at your waist.