Nothing ruins a good video like too much camera shake. And the best way to prevent shaking in your moving shots is with some kind of camera stabilizer.
Two of the most common types of camera stabilizers that are used in the film industry are the Steadicam and the Fig Rig. These systems are very effective. But most amateur film makers don't always have access to this kind of professional equipment. Fortunately, you can use the operating principles behind these systems to make simple DIY camera stabilizers out of materials that you have lying around. Here are two basic examples.
Step 1: Background: How a Steadicam Stabilizer Works
Following this principle, you can improve the stability of your camera by simply adding weight to it. The amount of weight that you need to add is proportional to the weight of the camera. As a general rule your weight should be at least as heavy as your camera in order to be effective.
The Steadicam is designed to accommodate large professional video cameras. As a result, the system has heavy counterweights and requires a substantial support system. But when working with small point-and-shoot cameras, the system can be greatly simplified. The support vest, the iso-elastic arm and the gimbal can be removed and the stabilizing weights can be attached directly to the camera. This is the basic design of handheld camera stabilizers like the Merlin stabilizer.
Step 2: Tripod Stabilizer
For slow moving shots, grip the tripod near the head. Having the center of mass well below your grip helps to keep the camera aligned vertically. For fast moving shots, grip the center column just above the leg section. Holding the tripod closer to the center of mass helps to keep it balanced during rapid movements.
Step 3: Background: How a Fig Rig Stabilizer Works
A typical point and shoot camera is about 4-5 inches wide. So widening the base to 18 inches can reduce the effects of random movements of a hand by as much as 75%. (A 1/4 inch vertical movement on a 4 inch base produces an angle of 3.58 deg. A 1/4 inch vertical movement on an 18 inch base produces an angle of only 0.80 deg.)
Step 4: 2 X 4 Stabilizer
Start by cutting off an 18 inch piece of 2x4. Sand both ends so that you don't scratch up your hands when using this rig. Then draw a line down the center of the board (9 inches from either side). Using a 1/4 inch drill bit, drill a hole straight through the center of the board at this point. Insert a 3 3/4" bolt with 1/4-20 threads through the hole and screw on the camera.(If you can not find a 3 3/4" bolt, substitute a 3 1/2 bolt and use a 1/2 inch drill bit to counterbore the hole on the bottom side.) Be careful not to over tighten the bolt.
This simplified design is not ideal because the hand grips are not in line with the camera. But it demonstrates how easily you can use whatever materials you have lying around to make a basic camera stabilizer.
Note: The actual dimensions of a standard 2 x 4 are 1.5 inches by 3.5 inches. So a 3 3/4" bolt should work in most cases. But since there is always some variation in both lumber and cameras, you may need to add washers or use a different bolt.