I think it's wonderful that you're looking to improve your skills in therapeutic communication. I am a registered psychiatric nurse and this is an area that I value greatly and I believe is the core of my practice. I also work with the addictions population and understand that they can be higher needs and sometimes more challenging; their situations (presently and historically) are usually quite complex.
As far as books go, I highly recommend Psychiatric Interviewing: The art of understanding by Christopher Shea. It was a text I used in school and goes through communication styles and techniques with a variety of patient presentations, diagnoses, situations, etc. It is an excellent book that I believe I will use throughout my career.
Another good resource could be Marsha Linehan videos on dialectical behaviour therapy (DBT), which is a therapy used on people with borderline personality disorder (often co-occurring with substance use and can be challenging to work with). Here's a link to one ->
As far as personal advice based off my practice, try to understand that people with mental illness and/or substance abuse issues are used to being treated poorly and can sometimes come across as defensive and challenging. Try to take a moment to listen to their concerns, and acknowledge their emotions. Verbally tell them that you hear them and maybe probe further into their needs. Often, there is some other underlying issue that they are not able to communicate adequately. Sometimes they just want to be heard and acknowledged. I know that this is difficult in jobs that are busy and task oriented, but recognizing your patient as another human being and giving them an ear can be very rewarding in the end. Another important piece of advice is when you notice agitation in a patient is to remain calm and communicate clearly. Be direct and ask them what they need. If this is unattainable or unrealistic, offer an alternative, or even offer some sedating medication.
Look into Peplau's theory of interpersonal relations... this will probably be a refresher from school. Also, it would probably be beneficial to look into Trauma Informed Care: Trauma Informed Care More often than not, people with mental illness and/or substance abuse have traumatic histories and having security called or being put in restraints can be re-traumatizing and lead to a lack of trust in health care.
Sorry to overload you with information, but this is an area I am very passionate about. Best of luck with achieving your personal practice goals!