Johnny had great advice!
The best was DON'T let them change the subject!!!!! I have found that they will have you jumping all over the place if you allow it. Just say, "Gee, I wouldn't mind talking about that subject some other time, but I have a one track mind, and this subject is really important to me. Could you HELP ME with this first?" Programmed to help--they will want to try to help you. However, don't try to make them look stupid. No one appreciates that. In the end, when it becomes obvious that they can't answer a question, allow them to save face. Just say that you still don't really understand. Then see if they would like a snack or something. Talk about the weather or the kids. Let it go. You will know when you have made your point. Even if they don't admit it to you.
Try always to ask. Never teach. Remember, you are the student. If it looks like you are trying to teach them, they will not listen. Just ask, and let them draw their own conclusions. This is an opening of the mind. Freeing them to think from a perspective other than the WTS's.
Here are some questions you may want to ask that I found personally helpful:
When Luke 12:32 is brought up: Look at entire context: Luke 22-34 "Jesus said to his disciples....." These are words spoken by Jesus directly to his earthly disciples in the first century. There is no reason to relate these verses to 144,000 member of a so-called flock. Ask them: according to Luke 12:22, who is Jesus speaking to in the 13 verses that span Luke 12: 22-34?
Where specifically is there any indication in the text of Luke 12:32 that the 144,000 of Revelation 7 and 14 are being spoken of? Where does Scripture indicate that the entrance into this so-called "little flock" of believers wouldbe closed in the year 1935?
Ask if they can show you a single verse of Scripture in the Bible where Jesus limits the citizenship of heaven to 144,000? If they point you to Rev. 7 or 14, ask them to show you where it explicitly says the kingdom is limited to 144,000. (There is no such verse!)
John 5:1 says "whoever believes that Jesus is the Christ is born of God." Ask--doesn't "whoever" include "everyone" and not just a select group of 144,000? If becoming born of God is open to "whoever believes"--and the requirement for entering the kingdom of heaven is being "born of God" or "born again" (John 3:5)--then isn't the kinddom of heaven open to "whoever believes", not just 144,000?
How do you reconcile the WT teaching that OT saints look forward to an earthly destiny with the Scriptural evidence that says Abraham, Isaac, Jacob, the prophets, and other OT saints will be with God in heaven? (If they disagree, ask them to read Matt. 8:11 and Luke 13:28 in the NWT. Then ask what these verses mean.)
Ask if they believe there are women in the 144,000. When they say "yes", ask them how they reconcile that with Rev. 14:4, which clearly states that the 144,000 are all men who have not been defiled with women.
John 10:16 clearly states that there will be one flock, and one shepherd. Not a two class system of believers.
Since the tribes of Dan and Ephriam were guilty of idolatry, do you think these tribes should still be listed in Rev. 7 as God's servants? Do you agree there is good reason for omitting them in Rev. 7?
Rev. 7:9-- Where in the text does it say the great multitude is exempt rom heaven? Where does it say they are relegated to live on earth?
Since the great multitude serves God day and night IN His temple (Rev. 7:15), and since God's temple is IN heaven (Rev. 11:19 and Rev. 14:17), doesn't this mean the great multitude is IN heaven? According to Rev. 19:1, is the great multitude on earth or in heaven?