Keep your camera as stable as possible. Although most video cameras have an image-stabilizer feature, it can't compensate for big bounces; this feature simply smoothes out jarring motions. Shoot using the LCD monitor, keeping your arms tight against your body. A camera will be much more stable this way compared to holding it away from your body. A pocket-sized or lightweight tripod can be a great help, whether it extends only a few inches or a couple of feet.
Lead the action. When panning to follow action, say, a float in the parade, don't center the subject exactly in the frame, but keep the frame moving a little ahead of the object. When you have enough footage, don't stop the tape right away. Stop the camera and let the object move out of the frame on its own before you stop recording. If the action goes on too long, you can edit it later.
Use good lighting. When outside, position yourself so the sun isn't pointing straight into the camera; this can result in flare and blooming. Blooming occurs when the pixel is overloaded by light, which results in a noticeable loss in image quality. Yes, silhouettes can be dramatic, but only if you want that as a special effect, not for a whole afternoon's footage. You want the sunlight shining on your subject, not in your eyes. If taping with manual controls, make sure your exposure is set properly for a good tonal range, black to white. If on auto exposure, check to see if compensating with a 1/2-stop over- or underexposure improves the image.
Get lots of coverage. Shoot a variety of angles of each subject and different focal lengths. When the band marches past, get a wide shot, close-ups of several instruments, or maybe crouch down to capture their marching feet or shots of the crowd clapping along with the music. Pay attention to the sound. If you plan to use live sound in your editing, record several minutes of ambient sound free of distracting noise or talking. Don't talk when taping; your voice is too close to the camera's microphone. If you want to narrate, do it later when editing.
Carry extra tapes and batteries. An hour of tape may seem like more than you need for the day, but you might find the best image at 62 minutes into your shoot.