Like distance healing, everyone will have their own process/opinion on this.
When I have a healing session booked in I will prepare and remove jewellery etc, however, Reiki can be done at anytime or place therefore sometimes if I'm out and a friend has a headache, I wont remove anything.
It's like visiting a hospital as a Reiki Practitioner your hands automatically start heating up/sending healing to those in need.
There are many people who will follow set rituals etc and say you must do x, y, z but Reiki is simple, just keep it simple :)
Hope this helps