It may seem obvious how to hold a camera, but providing a stable platform to keep the camera as stable as possible will help to create sharp images by ensuring there is minimum camera shake.
Use the left hand as a platform to support the weight of the camera and operate the focus and zoom, use the right hand to control the shutter release. Keep the elbows in tight to the body. Feet should be apart again to create a stable position. Kneeling and using the knee to rest the elbow on, can create an extra stable position for using longer lenses or in low light conditions.