Healing for most people requires a lot of energy use. You will need to have a clear mind free of any worries or problems that are going on in your life. You can use meditation or visual imagery to help you relax.
Breathing is always the best way to help you relax. Have a steady rhythmical breathing. On the inhale, imagine a pure white light coming into your body. On the exhale, visualize all negativity leaving your body. Send this negative energy into the ground so it can be neutralized.
Washing your hands and visualizing negative energy going down the drain helps. You can also use bells or chimes to help cleanse the auric field. Many other ways to clean an aura are burning incense, ask for protection and cleansing, rub Frankincense on your hands and wipe it around the auric field, and call for the Universal Energy to help you.
You can use these suggestions or in your practice, you may find something else that works equally well. Use that. There is no wrong in Reiki. If you follow your intuition, that is all you need.
No matter how much you want to help someone else, always take care of yourself first. Empathic people use their own energies and end up feeling drained and weak afterward. This also makes you vulnerable to illness and any negative energies that are floating around out there.
Direct the Reiki with your mind an use your hands as vessels to carry the energy to the other person. Let your intent be to help heal the person or to take away some of their pain. The intent is the most important thing in Reiki. Always have good intentions concerning yourself or your patients. Most importantly, practice the Reiki daily to keep yourself strong so you can help others.