I took an umpiring class this past Spring (2012), so I can offer what we were taught.
Regardless of whether a pitch is a strike or a ball, we were taught to wait a "tick" to be sure of what we've seen. If nothing else, this mindset helps one watch the pitch all the way into the glove.
If the call is a strike, one should rise from the slightly crouched stance, raise the right hand into a fist and pump it forward with authority and confidence while calling out 'HIKE'.
Why 'HIKE' and not 'STRIKE'? Simple, it's easier to call (especially for 7, 8, 9, or more innings), and it sounds close to the same.
The main point is to both call and signal the strike with authority. Oh, and swinging strikes are signaled, but not called out.
In addition, we're taught to make all strike calls, including strike three, where we're allowed a little bit of showmanship, while facing forward – not looking to the right.
Why? Well, home plate umpires in MLB, and I...