Your average Pagan is better-read and more articulate than your average Christian for whom apologetics is an unknown word, but in addition a minority of them actually have a relationship with their deities, and they're the hardest ones to reach in my experience of ministering to them, particularly if they were once evangelical Christians. Not impossible though, by the intervention and power of the Holy Spirit to reach hearts and minds.
The way we live our lives is just as important as what we say. We need to be above-board, totally honest even when it means saying 'I don't know the answer to that question but I will go away and find out,' and deeply in prayer, not treat them as the enemy to be feared. I wouldn't approach a rebellious 16-year-old in the same way I would a 50-year-old Alexandrian High Priest, although my basic message will be the same - that they are following a demonic deception and need Jesus.
There is no huge Wiccan conspiracy to take over the world - a small group can't even agree amongst themselves in the pub. But the spiritual deception behind Wicca and other strands of Paganism is real and it panders to man's basic sefishness and narcissism. 'Do what thou wilt' is as far as it goes for many of them. What average 16-year-old is going to argue with a minority (read 'exciting and semi-secret') religion which values the feminine highly, is completely non-judgemental on sexual matters with the exception of pedophilia and bestiality, is highly creative in an amateur dramatics sense, and promises a journey of 'self-development' along with acres of cheap velvet and tonnage of silver jewellery? It's handed to them on a plate and it fills the gap where modern Churchianity fails.