First and foremost, learn your laws. 9 times out of 10, you can quickly google something and find some answers. Beyond that, I think if you remember to hold your line in appropriate situations, but also understand that you are in customer service, you should be just fine. I'm going to tell you what I tell everyone:
1. law
2. your common practice
3. the bro deal you're willing to offer as a result of these particular circumstances
Demonstrating your knowledge in such a way sets a precedence of authority. When you then move through and say, "legally here is what the state says we can do, x is my common practice, but I know that you're going through something so I'm going to help you out by doing a, b, c". It's a nice way to demonstrate authority, hold your line, and come out of it looking like the good guy so you have a good working relationship. For you it's an investment. For your tenants, it's a home. Ultimately, it's the business of people. I think if everyone remembers that, you always come out on top.