1) Wash hair with a volumising shampoo and conditioner.
I'm not sure if these actually make a difference, but it's nice to pretend
2) Apply volumising mousse to the crown
I currently use VO5's Perfect Length's Bodifying Styling Mousse which seems to do the trick
3) Slick on some Tigi Bed Head Superstar Blow Dry Lotion
This is a similar price to the blow dry lotion. Equally lovely smelling, this claims to give some oomph to the hair, and I think it really does. This product doesn't last as long as the lotion, but a little still goes a long way.
5) Blow dry hair upside down
6) Use a large round brush whilst blow drying