Just say the truth. Don't embellish. Just give the facts to people.....For example, tell people that JWs don't think it's wrong to actually lie IF THEY believe that telling the truth to a person could hurt them. In this case it is called "theocratic war strategy" and the one who is not telling the truth about a matter can do this because the inquirer is one who is not "entitled" to know. And the Witnesses view is justified by using Bible examples of other faithful men who spoke untruth to a person because that one was not entitled to know the truth.
Another example of simply speaking the truth involves explaining why Witnesses refuse to be involved in birthday celebrations. Just tell the truth: the Bible only cites 2 bad experiences (involving death) to those that celebrated birthdays and only pagans got involved in such activities and since there is no record of Jesus celebrating his own birthday, "true Christians" must avoid this God dishonoring practice.
Can you think of other simple truths that show who Jehovah's Witnesses really are?