If writing a speech, you need to consider persuasive elements like emotional, ethical, and logical appeals to get your audience to accept the key points of your message.
First, appeal to their ethics... in case they have some. An ethical appeal would position you to discuss the lying that occurs on a daily basis. If you were speaking from the perspective of Winston, you could reveal what you do for a living by rewriting history for the Ministry of Truth.
Next, consider their emotions. People are motivated by fear. This is why the Party members obey Big Brother. You need to point out how expendable they all are. Express how death can occur. Express that people need to be saved. Point out that freedoms are not being given. Point out that the only reason the proles are given freedom is because Big Brother thinks they are too dumb to revolt.
Finally, use logic. In this instance you might consider using rhetorical questions. Ask them why Oceania always has to be at war. Why can't peace ever be possible? Ask them why it might be necessary that everything they produce is rationed and used if it is made in such abundance. Ask them if they believe that this style of living is the best that man is capable of.