But regardless of how wide you can set your aperture, when you're working with a shallow depth of field, the point of focus is equally—if not more—important than the background or foreground. The more of your image that's out of focus (creamy and/or dreamy), the more important the part that's in focus will be to the overall success of the image itself.
A lot less cut-and-dry than the nuts and bolts of aperture (or ISO or shutter speed, for that matter), teaching concepts like how to achieve a compelling image through use of a focal point isn't nearly as easy. Although much of photography is like math and science (numbers and measurements), some of it's more about intuition, vision and intention, and the latter is much harder to teach. Understanding that, there are simple things to keep in mind as you're creating your images using a shallow depth of field to help you achieve photographic greatness.
1. Choose your point of focus well. Working with a shallow depth of field means you have to make a choice as to what part or what subject within your image will be the focal point. Keeping in mind what compelled you to shoot this specific image in the first place will help you to identify the one thing that matters most to you. When you decide on the one element you really want to bring attention to, focus on that. When you're using an extremely shallow depth of field or even a macro lens, this can be tricky because your focal point may be just a small portion of the subject in your frame. Remember that even the tiny edge of a curling flower petal can be enough to make a strong visual statement. Sometimes bringing into focus something that normally may be overlooked or something a little unexpected is a refreshing approach to creating an evocative image.
2. Deliberately place your focal point within the frame. If the first step is the decision of what to focus on, then the second step has to be where you decide to place that focal point in your composition. This placement can help define the whole shot. Although there's no true right or wrong way to place your focal point—the possibilities are endless—it's important that whatever you decide, be deliberate. If you're going to center your focal point, then center it. If you want it to one side or the other in the frame, then do that. Just make it intentional.