How to effectively critique New Age ideas?

[NomenMihiNon]

...the magic of the church is proved not to work, but rather than rejecting magic the new ageist looks for magic that will work.

That is precisely what drew me to Wicca...well, what drew me to research magic and discover Wicca in the process. I hadn't really thought much about religion in my early teens, but the notion of gods that were symbolic representations of abstract forces seemed much more feasible to me than that of a literal pan-dimensional "person", along with the philosophy that humankind is a part of nature rather than somehow above it. But the desire to actively cast spells rather than passively praying was nonetheless my primary motivator. And the various books I read explained magic in a way that made sense to my young mind...except, of course, that there's no evidence for the existence of the forces and energies behind it. At first I was able to convince myself that the spells worked, but just not always properly (e.g. my love spell was misdirected and brought me someone completely wrong for me, as opposed to simply giving a shy kid the confidence to approach a girl he'd met only once before and just happened to know was a fellow musician). Or that maybe I just didn't have the ability, and my attempting magic was futile only in the sense of trying to teach an arthymic, tone-deaf friend to play the guitar. I guess at that point it would've felt like sour grapes to concede that magic simply isn't real.

The Woo-Woo crowd should be asked to present evidence, just like the jesus freaks.

The thing is the new agers are not usually so obnoxious about not having any.

Well, that's the thing. Christians have their "evidence", however flawed it may be, in the form of scripture and dogma. Whereas New Agers' beliefs tend to be based on an amalgam of theirs and others' speculations, which can be much harder to refute. But you're right, at least the New Age folks are more likely to actually discuss it as opposed to argue about it.