Here,
Connect your camera to your Mac using its USB cable and turn it on
Create a new Automator workflow and from the Image Capture library drag the Take Picture action into the workflow
NOTE 1: personally, I would leave the Delete image from camera after download option unchecked. This gives you a backup of the images from your session should anything go wrong with the workflow.
NOTE 2: The action should show you your camera name and if it is connected. If it doensn't show up, try switching its USB connection mode from Mass Storage to PTP.
From the Aperture library, drag the Import Photos action to the end of the workflow and set the project that you want each photo imported into
Finally, drag the Set IPTC Tags action into the the workflow after the Import Photos action
I usually use this to have all of the images tagged with my default credit, copyright, keywords, and other metadata so I don't have to do it later!
Save this workflow (file type should be Application) and place it in your dock
Now with the workflow app in the dock you can set up everything in the studio, frame your shot, and turn to your workstation. Hit the workflow app with a single click. If your camera is supported, this will fire the shutter and in a second or two the new image should be available in Aperture. You can use the arrow keys to select the new image and with the inspectors shown, you can immediately see the histograms, use the loupe to inspect image details (or just drop into full screen mode), and rank the image. Now you can make adjustments to your lighting or setup and repeat the process again. This is far better than inspecting images on the smallish displays on the backs of cameras and with a calibrated monitor, well, you'll really know what you're looking at! And the workflow helps you to fine tune your studio setup and adjust to changes quickly without the guess work of what the images will really look like.