While interviewing a patient, you will come to know variety of symptoms, and may observe many signs. Some are not needed for your current episode of problem you are investigating about. You need to learn how to keep those on a side and focus on the important points, and design a provisional diagnosis and treatment based on that.
Also as you are gathering history, do not interpret the signs and symptoms too quick, do not resort to scripts right away. There may be many other options to help the patient overcome the problems at hand without a pill. when diagnosing a disease try to include as many symptoms relevant to it, not to treat individual symptoms long term. Also keep in mind the duration many psychiatric meds need to be administered before seeing a response. Don't resort to too quick titration of meds. Treat tje diagnosis- which is of course a composite of symptoms, than individual symptoms. You may end in Poly pharmacy. Avoid polypharmacy