Ask the right questions, and keep the answers to yourself
To some, this is a no brainer. But I see many people, LEO or not, failing to ask the proper questions in order to actually get useful answers. Don’t offer up the answer when you ask the question.
Sometimes when I am looking for somebody, I know what vehicle I suspect they are in. When I am asking potential witnesses, I don’t answer the question for them. I wouldn’t ask, “Was he driving a blue Toyota Truck?” Many people won’t think twice and just agree. I always ask, “What kind of car was he in?” I often give vague choices when it comes to vehicle, because many people aren’t “car people.” I purposely leave out what I think the answer is. “Was it a car or a van maybe?” Make them say it’s a truck. Then get into specifics. “What color was it” “Small truck or a big truck?” Don’t ask if he had curly brown hair, it’s too easy to just agree with you.