I started doing energy work and spiritual healing using intention,prayer ,color, light ,Tarot and visualization as well as hands on and distance techniques many years ago before I ever heard of Reiki or attuned energy systems at all. I have found that various attunements can greatly focus the ability to consistantly work with energy but that it is quite possable to do very effective treatments without attunements or formal training.
Results do vary greatly between individuals and methods.
The healing practitoner channels and in some cases directs a flow but of themselves has no power the ability is not a rare and special gift but is potentialy available to each of us . Remember that what you can imagine you can create energy wise asking and inviting angels and other high vibrational spiritual beings to help you is a good place to start. To be effective at energy work it is of great value to know how to ground and center yourself connecting with the spiritual heart of the earth and Source and calling yourself together aligning your thoughts and personal entirety in a solid focused state. Seeing that the person you are treating knows how to ground may be the most valuable part of your healing and energy work sessions. Sensing Energy many people find that if they rub their hands together vigorously first they can feel energy more easily .