To start the thread, I'll go over a few things I used to do with my phone:

1. The Idle Hold
Basic creepshot technique, start recording with your screen off and just hold your phone. The downside to this is that it's quite obvious, less so in a crowd, but if there's a half-naked girl right next to you, people are going to know what you're doing. Regardless it's still one of the easiest and most reliable techniques (as far as I know).