For the catch of the your head it is much easier if you have someone assist you.
There are two approaches to the catch, with an iphone/ipad or with a digital camera & computer. In my experience I have found the iphone/ipad method to be the fastest & most reliable so that is the method I will explain If you would like to know the other method (which is actually very similar) visit: http://www.123dapp.com/catch/learn
For the iphone/ipad approach download the (free) 123D Catch app from the app store 123D Catch App
. Then create an account & log in.
You (person having their head catched) should be sitting down with enough room around them for the "assistant" (person assisting taking the catch) to walk around them taking photos keeping the catchee's head within the frame.
The environment should be as evenly lit as possible but does not require studio quality backdrops or lights (in fact it works better without them).
The catchee should sit as still as possible and stare directly forwards.