Information and tips on how to take portrait photographs:
Framing - Try to fill the frame when zooming into your subject. For portrait photography, you don't want to see the background especially if there are distracting objects present.
Aperture - Shoot with a large aperature setting which will reduce the depth of field. This will make the background blurry and out of focus while your subject is sharp. If there are distracting objects in the background, this will also help blur those objects out of the picture.
Be Ready - Learn to anticipate key moments in your subject's movements and expressions so you can capture them at the right times.
Experiment and Review - When you take portraits, have a close look at them and review what you like and dislike about them so you can improve for the next time.