In all of your witnessing, dwell on the positive, not the negative! Although you must be prepared on occasion to fight the Devil and his lies, and be able to answer all questions of anybody that asks of you, most of the time you should preach positively! (1Pet.3:15)
Try to approach others in a positive way with a positive attitude.--Be friendly, loving, understanding, compassionate and sympathetic, establishing as many points of agreement as you can. Dwell on things that you share in common, not points of disagreement!
Fighting false systems and false doctrines can be a temptation when you know you're so right and they're so wrong, but that's a negative type of preaching and witnessing.--And that kind of an attitude just doesn't win people, it doesn't win souls and it doesn't show love! The best way to attack points of disagreement is not by a frontal attack against the lies, but by just presenting the light, the positive! Preach the Truth, and that will take care of the lies!
Instead of preaching against things, let's preach Jesus and uphold Christ, and He will draw all men unto Him! (Jn.12:32)--Amen? God bless and keep you lovingly winsome!