Start your conversation on a positive note
While you start discussing with your boss, start your conversation with a positive note by asking his permission to speak. Compliment to his approach as this will add a positive tone to your feedback. This kind of positive approach helps to build your conversation much more constructively. While you are conversing with him, make him understand that you are not just pointing out on his mistakes but also you are trying to improve his strategy in a better way and make sure he accepts your point of view for some extent and thinks your views are valuable.