Here is a link to one of Mantic59's videos on lathering:
The Art of Lathering
Personally, I swirl my brush on glycerin soap (cheap stuff) for just 4 or 5 seconds before lathering with Proraso cream and that works really well. For a good lather you basically want to get the water right - not so wet that it falls off your face and not so dry that it cakes on your face.