With herbs as well as with other things there are different ways of working with them. Some Eastern ways of using herbs use principles of hot or cold herbs or yin and yang for treatment thinking.
Homeopathic use of herbs compares properties of a specific illness to the properties of herbs that can be used for a cure.
Western herbal traditions tend to require memorization of symptoms along with herbs to be used for those symptoms. None of these methods is more right or more wrong than another one. It is simply of investigating them enough to find what you are comfortable with.
No matter what herbal philosophy you like, you have to begin somewhere. One place to consider for starting, is what kind of health problems you and the people you will be using your herbs for, have very often.
Examples of this could be someone who has frequent headaches or someone who has respiratory problems. You will want the herbs to use for these frequent health problems available in adequate amounts.
I like to begin looking at the herbs that grow naturally in my area. When I move, I start with the herbs in the new area. You need to know what herbs there are growing around your area and when they are available. It is a good idea to find the best time to gather them for storage or making into oils or drying etc.
I also like to find out which local herbs are most versatile for multiple health problems. You can usually find several herbs that are versatile enough to reduce you need for a large variety of herbs to keep on hand. Professional herbalists often use only about ten main herbs for most health problems.
My next criteria are what herbs I can grow, either inside or out. It is much easier to use your herbs if you can grow them in a greenhouse so you have fresh ones whenever they are needed.
Many herbs used for cooking also have medicinal uses. I like to consider this when picking herbs to grow.
I also like to think about how easy or difficult it is to grow the herbs that I choose, in my local growing conditions. Gardeners use zones to describe how plants will grow in a certain area. Rainfall, air temperature and soil temperature are some of the criteria for zones and the plants that do well in different zones.
It can be helpful to have information on herbs available for when you need it. There are many good books available for growing and using herbs.
Good herbal books are even available for whatever philosophy of herbs you choose to follow. Which ones you choose is a matter of individual taste and you may need to look around for a while to find the right ones for you.