What's the secret technique for using one of these things?

You stick the pointed end under the trim by laying it flat on the windshield. Slide it over until one of the points catches behind the clip. Then gently pry the clip by racking the tool to the side. ( in the same plane as the windshield [do not pry up] ) that section of the trim should release ,then move on to the next clip. That tool does not remove the clip, it only releases the trim.

Good Luck

Slide the tool up under the chrome. The idea is to use the pointed ears on the tool to pull on the clip and release it from holding the chrome. Use caution not to hit the edge of the windshield with the tool.When you stick it under the chrome just slide it until you feel the clip,then pull down. the chrome should release.