A friend of mine asked me to light/grip a large 104-person, 3-hour headshot gig for a computer sales and setup company HQ'd here a few years back. He felt like his convection-cooled monolight system might not be up to the task of powering through so many shots very quickly over a three-hour or so shoot. So I supplied a Speedotron Black Line 2,400 W-s pack and multiple fan-cooled flash heads, set pretty low in Watt-seconds, so he could shoot extremely quickly for those kinds of people who are tough to shoot. Being able to shoot super-fast mini-sequences can oftentimes help people who tend to "freeze up".
Anyway...as Tirediron mentioned, it's a good idea to have on-hand some necessary supplies, like disposable combs, a hand or table mirror (or two!) and let me add--a good, new lint brush, or failing that, a large roll of masking tape that can be used to make an impromptu lint pick-up tool by wrapping some tape around the subject's hand, with the sticky side facing outwardly, so they themselves can blot at and pick up lint, pet hairs, etc, especially from dark shirts and blouses. Clothing needs to be clean and hair- and lint-free! You want to do almost NO retouching!
One tip: when shooting indoors in offices with flash, set the camera's white balance to a pre-set or custom WB. Do NOT allow the camera white balance to be on AUTO, since it will almost invariably sense the prevailing fluorescent lighting. And in mentioning fluorescent lighting and White Balance: set the camera up in Manual exposure mode, and keep the shutter speed constant, and fast enough so that there is no mixing of the flash with the ambient lighting! Keep the shutter speed around 1/125 second, which keeps the fluorescent light from showing up, and keeps the actual exposure as "all flash lighting".
If your flash units are weak, or are slow to recycle, set the camera's ISO level to a higher-than-normal ISO value, such as 250,320,or 400. With good, adequate lighting, and a decent exposure from the lights, there should be fairly minimal noise. Elevating the ISO with studio flash-lit pictures is typically not a big worry.
Make SURE the backgrounds are good! Don't shoot garbage shots. Shoot in RAW + JPEG small mode so you have an EASY-to-review set of JPEGS that can make culling the set a matter of doing a slide show of the camera-created,small JPEG files, and kill-filing the duds and blinks, and then pulling the corresponding RAW files out of the main editing collection. Secondarily...the straight out of camera JPEG files can or could be delivered as a "bonus" item to the company...and they might even run directly with those, depending on how well-shot they were.
When shooting this kind of stuff, assembly-line, flash-lighted portraits, it helps to have the SOOC JPEG setting set,beforehand, so that the SOOC JPEG images look "great". That means some in-camera sharpening, like 6 or 7 on a scale of 0-10, the tone curve set to the right degree of contrast, and the color saturation a bit above normal, yet not Nikon-like "Vivid", which is clown-car coloration. By pre-setting the Picture Control settings in RAW+JPEG shooting mode, you can have a basically, almost-perfect SOOC flash-lighted shot that looks GOOD!, but of course, the RAW files will not have these parameters set in stone, and the RAWS can be edited any number of ways.
Good luck. I hope some of these tips will be helpful to you.
