Really only three or four things you ought to say during a stop

“( Name and address, or license registration and insurance if in a vehicle)” -required by law pretty much everywhere.

“I’m exercising my right to silence. I will not answer questions without a lawyer”

“I do not consent to any searches”

“Am I being detained, or am I free to go”- say this one anytime you think the officer might be done with the reason he stopped you, because it “starts a clock” of unlawful extension

Pick whichever one makes the most sense at any given moment. Don’t say anything else. If the officer says you are free to go, leave.

As for what you can refuse, you really can’t during the stop. You have to fight in court. LISTEN CAREFULLY to the words of the officer and do not respond to QUESTIONS, only ORDERS. They are trained to ask you to do things that might be unlawful if they were orders, like can you step out of the car for me please, can you follow my flashlight for me, can you roll down your window all the way. If you are unclear, ask “are you ordering me, officer?”

If any part of the stop was unlawful your defense attorney can iron that out later in court (and if so, typically everything occurring after the unlawful gets thrown out)

If you want to go a step further and be polite etc, know that many police won’t give you brownie points for it, but if they ask you questions like “where are you coming from” or “where are you going” or “who are/were you with” redirect your answers only to plainly obvious facts about YOURSELF ONLY and the PRESENT time, e.g. “I am out for a drive officer”

Caveat: IANAL, this is not legal advice

Source: SWIM has extensive experience in this area