Doing sniper surveillance (camping in the back of a surveillance vehicle with a DSLR or camcorder) is the most effective way to get the money shot. You’re supposed to be a ghost. No one should even notice you, much less see you, but I’ve always preferred engaging the subject face-to-face. Come up with a cover story (Jehovah’s Witness, landscaper handing out flyers, asking for directions, etc.) and then talk to the subject with your phone in your shirt pocket recording the whole thing. I want my subject to remember the face that betrays his trust.