As long as we're on the topic of portraits, here's a quick exposure tip that will soften backgrounds nicely: use the portrait exposure mode. This mode, usually indicated by a silhouette of a head on the exposure-mode dial, automatically selects both shutter speed and aperture for you, but it gives preference to selecting a large aperture. Because large apertures create less depth of field (near-to-far sharpness) your portrait subject will be sharp but the background will be naturally soft.
Other things that contribute to a shallow depth of field are the focal length of the lens you're using (longer lenses and zoom settings have less inherent depth of field) and subject distance (the closer you are, the less depth of field there will be). So if you want to help the mode along at creating a soft and pleasing background, shoot portraits with a medium telephoto lens or zoom setting and work close enough to fill the frame with your subject.
And don't forget to read yesterday's post about using flash with outdoor portraits!
10 hours ago