In the beginning, there was the 10 second dash. In my early days, that's how it was. I'd set up precarious arrangements of various household objects, in lieu of a tripod, set the timer, and make a break for it. Thankfully, Flickr is a wonderful teacher. Through the Project 365 group, I heard that remote triggers existed, and in various forms. They use infrared and a sensor on the camera itself, and they're inexpensive. I chose this little guy:
There you go, that's the trick. This little guy enables you to either push the button and instantly take a shot, or to give yourself 2 seconds of prep time before the shutter snaps. You don't have to worry about accidentally moving your camera, running back and forth, or having to drag a lackey along. There are a variety of types, this just happened to be the first I've found, and I like it.
Why is it never in the shot? It used to be.
This tiny thing gives you the freedom to take however many shots you want, without disturbing costumes/props/any setup, or making you run back and forth. They will have range limitations, and you can get more robust ones. Unless you're going quite a distance, it usually doesn't come into play; though you may look a little funny trying to line up the remote and the sensor just right.
That's all there really is to it! No man behind the curtain, just a teeny and handy bit of technology- readily available at your online superstore!