The biggest mistake you can make in trying to talk convincingly is to put your highest priority on expressing your ideas and feelings. What most people really want is to be listened to, respected, and understood. The moment people see that they are being understood, they become more motivated to understand your point of view.
It is true from early habit, one must make love mechanically as one swims; I was once very fond of both, but now as I never swim unless I tumble into the water, I don't make love till almost obliged.