Depending on the type of healing you are doing. May it be crystal, herbal, reiki, etc. And what you are healing. The best thing to do would be to cleanse the area by smudging. Then cast a circle, and do the spell. The circle is useful because it holds the healing energies in and around the area you are working. You might want to cleanse yourself before doing a spell as well by taking a shower or bath. After that, you may want to cleanse yourself.