Shutter. Aperture. ISO. If you want to have full control over your photos those are the 3 things you must master and understand (with giving focal length an honorable mention). To best describe them I will take you through my process when taking photos but by all means make your own and do whatever feels comfortable.
Step 1: ISO. This will determine how sensitive to light your “film” is. 100 = not so sensitive and higher equals progressively more and more sensitivity. In other words… sunny day at the beach is 100 and evening cocktail party is 2500. I set this first because along with determining how sensitive you want your camera to be at its core (the “film”) it determines the quality of the photos. The higher the ISO the more grainy the photo is.
Step 2: Aperture. Aperture controls the depth of field. Lower aperture, like a 2.8, is a very shallow depth of field. Higher aperture will allow for more and more in focus as you go up. The lower the aperture number the more light is being let in and, of course, the higher the number the less light will be let in. Setting this second will allow for you to choose your desired depth of field. I mentioned earlier about the honorable mention focal length – which is how far zoomed in or our you are. Zooming in more on the subject will create a shallower depth of field than zooming farther out… so keep that in mind.
Step 3: Shutter. This is last because, personally for me, it is the least important and allows me to adjust the shutter accordingly so that the previous settings hold true to the reasons I set them. I am not saying shutter has no effect, it does. Faster shutter will give you crisper images and show less movement. Slow shutters will allow for more light in but give you motion blur depending on how low you go. The majority of the time, when taking a “normal” picture the shutter is the easiest to adjust to allow for correct exposure. Be aware that if you are at a 100 shutter speed and its gets darker for some reason causing you to go below about a 50 shutter speed, you’re going to start seeing a good amount motion blur from a moving subject or moving the camera.
This is my personal preference and I do stray from it sometimes but overall it has worked out the quickest and easiest for me in most situations. If your environment changes go back to step one and start again. The advantage of using manual mode is being able to set how you want each photograph to look manually BUT just like a manual car you can’t jump from park to 4th gear without going through the proper steps first.
Hope this helped in some way. Let me know what your processes are or if you found using a better mode is better for you.