When working with busy executives, you only have a short time to be disrupting their day. So you have to be ready when they are. Get there early and set up, test and be ready for them, don't make them wait!
Another Item to consider is how much equipment to bring. When I'm photographing executives, I try be a minimalist. Think about it, you are in and executive's office you don't want to bring in booms, huge light stands, gigantic lights, keep it simple.
This was my set up for a portrait that was published in Progressive Grocer Magazine.
When ever possible, I like to use a simple executive portrait set up. This is made up of my camera on a tripod, two to three Nikon SB900's on lightweight stands. For my main light set up I will use one 40 inch umbrella that yields a soft light. I bounce some of that light from the side to fill in light in the side of the face. I use the Lastolite TriGrip white side as my reflector.
A second SB900 is on a small stand in the background pointing directly at my subject's hair, to create a nice highlight. This light also acts as a separation light to create a rim around the subject to "separate" them from the background. I can control the spread of the light with a grid spot. I use the HONLPHOTO version called the speed grid.
The exposure is pretty simple in that I first set up the camera and get an exposure that fits for what is outside the window. Next I fit the lights to meet that exposure.
I use the Pocket Wizard Flex TT5 as the remote firing device for the strobes.
Here is a lighting diagram that might help you on your next executive portrait on location.