Simply put, the focal point is where you want the viewers of the photos to focus on and is the most important part of the frame. Using focal points effectively will intrigue viewers and draw them into your photos. Typically, for real estate photos you want your focal point in the middle of the room.

Color contrast can also change your focal point if there is an area of high contrast as it naturally draws in the eye. Such as, a bright red accent pillow on a white couch. Be mindful of how color contrast is impacting your focal point. 

For real estate photography, you want to shoot your depth of field at an aperture of f/8. Depth of field refers to the distance between the farthest objects and the closest objects of the image and how they are focused. It does not take into account elements that are not in focus.  One way you can control depth of field is by adjusting your aperture. In general, smaller f-stop numbers produce a more shallow depth of field and larger f-stop numbers produce a larger depth of field. Using an aperture of f/8 in real estate photography will give you the greatest depth of field and have your entire frame in focus. 

Here is an example of a photo with a shallow depth of field. Only the closest elements are in focus.

Here is an example of greater depth of field, where the entire frame is in focus.

For more creative photos, the rule of thirds is often used as a guide for your focal point to get a compelling shot. Although you may not use this much for real estate photography, it is a good principle to know as a photographer. 

The rule of thirds breaks up a frame into thirds, both horizontally and vertically. Following the rule of thirds to place focal points along the grid lines and not in the center in order to achieve better composition. It is helpful for highlighting the background and balance of empty space in your photograph.

Here are examples of photos that use the rule of thirds effectively: