I have had good luck with Kreg’s Pocket Hole joinery, but have always been somewhat frustrated at the tendency of the two pieces from moving up out of alignment. I have tried various clamps, but even they got to be awkward. Finally, I found that after drilling the hole and bringing the two pieces together, I take a long, thin drill bit, insert it into the hole as far as the surface of the second board and drill a short distance to create a starter hole, it’s then possible to use the so-called self-drilling pocket screw without having to use any clamps.
– Jack Waddington