Depth of field can be critical in good composition. We relate depth of field to the size of the aperture hole, or f-stop. The larger the hole, the smaller the f-stop, the less detail that will be in your background. Remember that the larger the hole, the faster the light pours into your sensor, so we need less time to collect the light, hence the background and mid-ground being blurry.
Different lenses allow an f-stop of f/1.4 to f/45.0. While f/2.8 will show almost no background, an f-stop of f/22 will show tons of detail. To increase background detail with a larger f-stop, add light, or bring the subject closer to the source of light. Remember that when you try to turn up the shutter speed to capture detail, you will wash out the foreground, and lose detail to saturation. This appears as clipping on your histogram where the light peaks are ‘clipped’ off at the sensor’s saturation point.
Don’t fear saturation all the time. Maybe you want that ghostly pale look for a reason you’ve decided. Likewise, don’t fear a shallow background all the time… A lot of distraction will detract from your subjects. Besides, life is chaotic and you can capture that with your photos. This is one case where soft focus works. Think to when you can’t change the background and it is cluttered… intentional blurring will make your subjects stand out and negate marring elements that cannot be rid of. You can blur trees, and bushes to give a general green background while making a deer stand out in highlight. You can blur a power line that detracts rather than adds to the photo.