You can make a healing wand out of anything; you can even use your hands to heal and skip the wand altogether.
The most popular form of healing wand is a crystal wand, or a wand with a crystal point (usually clear quartz or rose quartz). If you want a solid crystal wand you should just buy one, cleanse it, and charge it.
Otherwise here are some simple directions: buy a wooden dowel from the hardware store (or use a branch!) and attach a quartz crystal to the tip using some copper wiring. Decorate the wand with words, colors, or symbols that help you to activate your healing magic.