Here are some of my ideal settings for getting the best results with Skanect.
Feedback Quality = Medium
Offline Recording = All Frames
Force QVGA = OFF
Track Loss Detection = ON
Depth = Depth & Color
Uplink Color Gain = Locked on Record
Watertight = Low/Medium
Resolution = 2/3 mm
Inpaint Colorless = ON
Highest Quality = ON
Face Mode = ON (Person) otherwise OFF
Create a config.ini file with the line (center-y-as-height-percent = .75) and upload it to "Prepare -> New -> Config file"
(This will allow you to start scanning at someone's face as opposed to their torso 75% height level) Don't forget to change it if you want to change your default starting point.
The best scans that we have seen use bright but diffused artificial (not sunlight) lighting from multiple sources to illuminate the subject and eliminate shadows. What I have done in the past is attach 1 or 2 of these lights to the back of my iPad with velcro when I am going to be at an offsite location with unknown light sources.
You want your Bounding box to be just a bit bigger than your subject but not overly big or else you will saturate the results. For instance if I wanted to scan a standing person I would typically set the following:
Bounding box = 1.1 x 2.2 x 1.1
Aspect ratio = Height x 2
If the person is taller than 6' you may need to increase the box size
If I just wanted to get head and shoulders I might use.
Bounding box = 0.6 x 0.6 x 0.6
Aspect ratio = Normal
When you are starting a scan of a person start the capture at the face first take one step to the left to capture the side of the nose then continue to the right and around the subject in a spiral fashion (similar to a tornado). I would not recommend going back to the person's face again if you can avoid it.
You may need to make a sweep up the back at the end and do a top down view in order to capture the top of the head.
You want to aim to get a continuous 30 FPS in Skanect when scanning. Some great things to try. Ensure Skanect is the only program running. Disable your firewall or antivirus to see if that helps to speed things up.
Finally, if you have the ability to invest in a CUDA 2.0 or higher NVIDIA GPU this will also help to get better results.
Hopefully you will find you will get better results by following the above steps. Once you get into the swing of things you will soon adapt to your own preferences. Here's a sample file for you to see using Skanect 1.8 + Structure Sensor + iPad Air 2.