The "answer in full sentences" rule
This is the single most important coaching note. If we ask "what's the biggest challenge your team solves?" and the subject answers "scheduling delays," that clip is unusable on its own. If they answer "the biggest challenge our team solves is scheduling delays in commercial construction projects," that's a usable soundbite. Tell every interviewee this, twice, before the camera rolls.
Wardrobe
Solid mid-tone colors work best. Avoid pure white (it blows out under interview lighting) and pure black (it sucks in shadow detail). Avoid stripes, herringbone, and busy patterns (they create a moiré effect on camera). Logos on the chest are fine if the company brand is part of the story; otherwise skip them.
Don't send a script
The fastest way to get a wooden, lifeless interview is to send the subject a script to memorize. Send them 3 to 5 prompts you'll be working through, suggest they think about specific examples and stories that come to mind, and let the actual phrasing be theirs on the day. Memorized answers always look memorized.
Day-of basics
Schedule interviews early in the day if possible. People get more articulate after coffee and less articulate after a 3-hour meeting. Make sure phones are silenced (not just on vibrate; that's audible on a lavalier mic). Have water available; talking on camera dries you out fast.