Use the strap of your camera to provide support. Wrap the strap of the camera around your wrist and then hold the camera with both of your hands. Take caution not to cover the lens or the flash while taking a picture.
You can also use your body to provide support and thus keeping the camera steady. While holding the camera horizontally, make sure both elbows are tight and close to your body while simultaneously using the mass of the mid of your body to stay steady.
And if you wish to take a picture while holding the camera in a vertical position, keep one arm close to your body for support and stability with the other arm raised above your head such that it is horizontal to the ground.
Try to stay still and stabilize your body. One thing you can do is to breathe out and hold your breath while taking a picture or shooting so there is no movement because of your body movements.
Tripod is an equipment of choice to stabilize a camera, keeping it steady if you are planning to take shots which require especially longer exposures. You can also consider using a beanbag as a stabilizer in conditions where a tripod is not available or too cumbersome to carry. Place the beanbag on a stable surface and support the camera on top of it. Monopod can be used in cases when the camera is to be kept mobile while stable at the same time.