I find it hard to engage Mormons and JWs and others, mainly because I find it so hard to retain key points and stuff that I need, and that I get JWs and Mormons mixed up re beliefs etc. I have read good books on the subject several times, but the one thing I can really remember every time is David Reed's comment at a conference: "If you just get 5 minutes with a JW, share your testimony and talk about Christ."
Perhaps I should get a couple of crib cards and leave them in my wallet. Because you usually get a warning, you can see them coming a long way off!