The gathering and preparing of herbs is a specialized work, but one which anyone of average intelligence may safely undertake with proper training. (There are also special storehouses and laboratories that cater to the Herbalist by supplying crude herbs, tinctures, and all kinds of preparations.)
It has been said that the "Nature Doctor", as a natural healer, should be a psychologist, to study the character and symptology of the patient. She/He should also be a student of the body. In addition, she/he should be a dietician, to study the most suitable diets for the patient; and a person of general knowledge about her/his subject and people in general. I would certainly recommend that the student study anatomy and physiology to gain a working knowledge of what is involved in a cure.
Before you go collecting herbs, decide on just one or two species for each trip. Most important, find the best time of day to collect them. Having selected what plants you require, pick only those parts which you will be needing for drying and processing, otherwise you will not only be taking home waste matter, but you will be stunting the growth of next year's crop.
Before picking plants, check very carefully for their various attributes to make sure you have the right one. Many different plants have similarities, enough to cause confusion. You cannot spend too much time studying illustrations, photographs, etc., to learn to recognize the many different species. When collecting herbs, make sure you do not damage the plants as you pick them. Make them up into small bundles. Do not crush teh plants, as this will limit the amount of goodness you will get from them. (Also, please give an offering of tobacco and a prayer to the Great Spirit for the taking of the herbs. Thank the plant for allowing you to use it.)
When selecting plants, always try to refer to them by their Latin names, for these never change. If you use the common names, you can become confused, since most herbs have many different common names. Depending on where the herb is found, it could have as many as twenty different names by which it is known. But each plant has only ONE Latin name. Remember that PLANTS SHOULD ALWAYS BE REFERRED TO BY THEIR LATIN NAME FOR POSITIVE IDENTIFICATION.