Animal shapeshifting? I personally practiced that long time ago, and it is more on a spiritual level than on energy level. You must connect with the spirit of the animal and long story - short, you become closer with each meditation and when the time is ready the spiritual vibrations with you and the animal you have chosen will be on the same frequency (officially the status will be updated to close firends) and it (the spirit of the animal) can soulbound with you. Don't expect physical changes atleast not from the first time
But in time (atleast what i've experienced was small changes in the eyes and a bit of blond hair on my forehead)
I had chosen the spirit of a cheetah because it is the fastest living creature out there and the first times when i tried to shapeshift (you need to be in a forest or somewhere out in the nature out of civilization) i felt that something wild was in me and I wanted to walk on 4 legs ( so i did xD) and the most strange and awesome thing was that my hearing sences, eyes, smell had sharpened and the feeling inside of you - woah.
This is one part and the other is Invocation - to invoke the spirits from our and many others dimensions (but this is more to magic and spiritual energy and the subject was powers with the mind) sorry got carried away hope u don't bann me for this xD