If you look closely at most acupuncture charts you will usually see the meridian lines on the chart and the pressure points are on the lines.
Most acupuncturists will first talk with the client/patient and have the patient fill out a questionnaire in much the same manner as a regular Western medical office. Then, the acupuncturist will do at least one version of Traditional Chinese Medicine diagnosis. There are many different diagnosis methods including but not limited to looking at the tongue or eyes or end of finger tips but the most common traditional method is Pulse diagnosis. Advanced masters can diagnose by sight.
To perform pulse diagnosis the acupuncturist will place their fingers on the palm side of the wrist and feel the energy flow through the soft tissue of the wrist. The sensations being felt for are a fast, slow, extra strong or extra weak pulse in one or the other of the meridians. Also, the practitioner is feeling for heat/dryness or wetness and/or any sensation that distinguishes one meridian from the others. Any difference in sensation indicates an imbalance in one or more meridians which in turn reflect physical problems or maladies. The idea in acupuncture is that by adjusting the meridians the physical state should also improve. A very sensitive touch is required to diagnose this way but it is simply a matter of practice to learn it.
Once the diagnosis has been made then the acupuncturist will consider the treatment options and insert the needles into the correction points. Then, the TCM physician uses sensitive touch once again to turn and adjust the needles so that they are influencing the flow of Chi through the meridians and hence adjusting the Chi flow through the entire body. Multiple follow-up treatments may be required to get the body to go back into balance and to fully accept the chi flow adjustment.
Historically, in China once the needles have been inserted into the patient then the TCM practitioner will influence the chi flow by using their hands and fingers to direct chi through the needles without touching the needles or the patient. This method is rarely practiced today as most practitioners do not have the knowledge or skill required to properly do it. Also, the Chi flow can be directed without needles. Using energy to direct the flow of Chi is taught in our more advanced programs.