1. Focal Length (What lens you will use)
2. ISO (Film Speed)
3. Aperture (F)
4. Shutter
Here we go
Step 1. Before you take a picture with your camera, you need to think what are you going to take, portrait, scenery or street photos. Thus you can consider what lens such as 28mm, 35mm, or 135mm...etc.
Step 2. Next, the priority is how much light we have into the first consideration. If you take a photo at home with limited lighting, you may select higher ISO such as 800, 1600.
Step 3. Then we can consider the aperture, smaller stops (larger f numbers) produce a longer depth of field, allowing objects at a wide range of distances to all be in focus at the same time. Thus we may take F5.6 or F8.
Step 4. As long as you have chosen above as priority, if the lighting is not allow and any shutter speed with slower than 1/60sec. you will need a tripod to support or find a position that you can place your camera on it.
Good illustration from Anna Wu Photography here:
