* Act like a normal, sensible person. Don't try to provoke them, and don't give them any reason to escalate the encounter.
* Don't allow police in your home without a warrant.
* Affirmatively deny consent for searches. This includes your home, car, and personal belongings.
* Assert your right to remain silent.
Unless you're reporting a crime where you're the victim (and, sometimes, even then), you should only talk to police with a lawyer representing you present.
Aren't police allowed too search all sorts of things with easy excuse? My refusal is a form of escalation especially since they can arrest me on whatever, then let me go, and that alone could jeopardize my immigration status (all those visa questionnaires starting with "have you ever been arrested").
By calmly and clearly asserting your rights, you're preserving whatever slight edge you have. All the better if there are witnesses or recordings.
Allowing searches, answering questions, fleeing, or resisting, all work against you. Stating you don't assent, clarifying that requests are orders, and complying under protest, are options.
"Good (morning|day|evening) officer" is a good starting response. It makes clear that you aren't rattled, and concedes nothing.
And no, immigrants (or minorities) don't start with a fair break. But you can keep from letting that disadvantage erode further.
Slow movements, hands in sight, etc., all help.
Chances are that if they were going to arrest you after refusing to talk or allow them to search, they were going to arrest you anyway.
The problem is asserting your rights and not acting like a docile thankful citizen can get treated as escalation in and of itself.
And I'd be way more receptive to the 'a few bad apples' argument if the whole thing didn't react to any charges or investigations into those bad apples as an attack on the whole followed by at best a retirement right before they get disciplined and fired (where they usually just go work for a different department or security).
https://sacramento.cbslocal.com/2017/11/29/man-arrested-for-...
That's why you have to act like a sensible, docile, thankful citizen who also asserts your rights. Do not act "normal". Normal gets you hurt.
Whether "normal gets you hurt" or "gets you a professional interaction" says more about your particular personality than anything else.