If you're the designated camera-person, make sure that you focus on your own skating and stay safe, regardless of who you're filming or how many skaters you're filming. Don't look through the camera lens and pay too much attention to your camera work, focus on staying on your board and balancing.  If you're filming yourself, consider setting up your camera on a tripod. Mark the spot on the concrete that's the center of the frame with sidewalk chalk, so you'll know where to pull your trick. If you're skating and filming others, don't try to get too fancy with your footwork while you're doing it. Just focus on smooth skating and keeping the camera steady to give their tricks the camerawork they deserve. Whether you're standing still or skating along with the people you're filming, you want to make sure you don't get too caught up in the fun of filming and lose track of where you're going. Becoming an obstacle between you and your buddies pulling off a trick is a good way to get your camera cracked, your face busted, and to lose some skater buds. Even if you're posted up at the bottom of a set of stairs, toward which your friends are jumping, stay curled up and stay in one place. Don't move elsewhere to Try to find another spot. Stay steady and let them work around you. Stay far enough back from the staircase to give them room enough to land the jump and roll for a few feet without hitting you, giving yourself enough time to get out of the way if necessary. Start filming early and keep filming late. When someone stomps something big, always keep the camera rolling. You’ll never have too much footage. You always want to do this to avoid missing those rare moments of brilliance because you're too concerned about your tapes. If you go out with a blank tape, make sure you come back with a full one.  Don’t try to edit on the fly. Worry about editing together the footage later. Just think of yourself as a collector of moments for the time being. Your job isn’t to finish the video today, it’s to make sure you get all the best shots. Film the fails, too. Don't just worry about filming the tricks. A roll full of nothing but spinning boards get dull after a while, so it's a good idea to film your friends talking smack, comparing scraped knees, and joking around. Perform for the camera. Footage of disembodied feet doing a trick isn't much fun to watch. It'll look jerky, confusing, and less impressive to only see half of your friend pulling off a sick trick, so it's important to set up your camera to keep the whole skater in the frame during the entirety of the trick. Let the viewer appreciate the full range of motion and athleticism necessary in pulling off a trick.  Try not to zoom while using a fisheye. Most are designed to be used in the telephoto position and zooming will cause it to go out of focus. Messing around with the zoom too much will also make the film appear super-shaky. Don't try to get too fancy with it, just be there to document the tricks and catch the magic. Don't film with a fisheye for everything. Specially, fisheye lenses should be used for big gaps or sets, not more compact tricks. If the trick is going to be big, use a wide angle or fisheye of .63x - .3x is suggested for an added wide-angle flavor and for making sure that you get the full range of side-to-side grinds and other things that will require a big range of motion. Use manual focus. Don't turn the option of steadyshot on with a fisheye, it will distort the vignetting. A common mistake that beginners make when trying to film tricks is moving the camera too much to Try to focus on the skater, rather than letting the trick come into the frame. Focus the camera on the stairs or whatever other obstacle will be involved in the trick, until seconds away from executing the trick.  Point the camera up so you have both the body of the skater and the entire stairs in focus. A common successful angle is at 3 feet (0.9 m). from the bottom of the stairs, out of the passing way with you  crouched down so  camera almost touches the ground.  Start recording when the skater is about 5 or 10 feet (1.5 or 3.0 m). away from the top of the staircase. Leave as little ground in the frame as possible, if you can, to make the trick look much better. If your bud’s having some trouble sticking the jump, having less of a reference point for the after-trick wobbling and balance-grabbing will make the footage look that much better. Frame it so that we see the skater upon landing, and not much else. Another classic shot will require you to move while you film, preferably skating. If your friend wants to try a long grind, or a set of tricks along a line, you'll need to hop on your board and run parallel to the trick. Set the camera to focus on the skater, setting the depth of the field so it won't be blurry. Try to maintain the same distance from the skater as you film. It's important to film instead of jogging or walking quickly, since the footsteps will jostle the camera and make it difficult to watch. Skating will help the footage to stay nice and smooth. There are the common ways to film, but the choice of the angle, the way you want to edit, and the shots you choose to keep is up to you. Practice until you get it right. Keeping track of the distances you are using, and the distance that gives the best picture. Try filming at different times of day. This will give you more footage to work with later when trying to add diversity to a full-length film.

Summary:
Focus on your own skating. Stay out of the way. Keep the camera running. Keep the whole skater in the frame. Film the stairs, not the skater. Help the skater stick the landing. Capture a grind by skating at the same speed. Be creative.