Good question! The best way is to organise your thoughts and mention the 3-4 main problems which you want help with. Then try and describe each of those AND the impact of each on your life. Specific examples would be helpful, like I can’t sleep at night and this makes me drowsy and lethargic in the daytime OR I am unable to control my thoughts and this prevents me from concentrating on my work/studies.
Secondly, listen to the Psychiatrist when (s)he is trying to explain to you the possible reasons for your feelings or thoughts or behavior. Ask if you do not understand or disagree with an interpretation or suggestion.
If you have been unwell in the past and have prescriptions and/or blood tests/imaging studies, please bring them with you and arrange them in date order. If possible write down the period when you have been unwell and when you have been well. Sometimes making a graph can be easier and helpful.