The most effective way to secure your camera while shooting is with a tripod. These are sturdy, rigid three-legged supports that have flat platforms or heads on them to hold the camera. Most tripods have a head that has an elevator center post. You attach your camera to the post and it is raised or lowered by moving the post up or down. An elevator eliminates the need for readjusting the legs during last minute adjustments.
Tripods are available in assorted designs, materials, sizes, and weights. Heavier tripods tend to be the sturdiest and give the best support, but if they are too heavy they are hard to carry around. The heavier your camera is, the heavier and stronger your tripod should be. If the tripod is too light and affected by wind you can hang a weight from the head to stabilize it. Table top tripods are available along with mini or compact models that can fold away into a small bag or case.
Tripods can range in price from about $20 to several hundred for a kit.