By not sounding like a lawyer. The more technical and obscure you sound, the more suspicious of you they are. You have to leave the legalisms at home and learn to talk like a real person again. By not acting like a huckster who is arguing the case before the jury even knows what it is. By not pushing jurors for promises and commitments about how they are going to decide the case in various situations.
People are suspicious of being pinned down before they even know what the options are.
By being plausible and reasonable, and not trying to sugarcoat your side of the case. By being plain, simple, open, and receptive. You are the most important witness in the case. But you are more than a guide. Hold on a second, you say.