There are 3 things you need to gain to get fast in autocross.
1) Seat time.
2) Seat time.
3) Seat time.
Everything is secondary to that. Everything. There are local drivers who could put a fridge on wheels around a track faster than a new guy in an F430 (slight exaggeration, but only slight). Once you get close to the machine's capabilities, then you need to start worrying about tires and chassis dynamics and left foot braking and everything else that separates a driver from a racer. But a fast car with a slow driver is still going to be a slow car.
I've read before that a particularly adept driver can come close to fully utilizing a stock-prepared car after 2 seasons. This sounds about right to me. The depth of my advice here is to add about 10psi to your tires, and try not to hit any cones. The rest will come to you. And yes, get ride alongs whenever you can, beyond being a good learning tool they are wicked cool.
EDIT: The Focus is certainly capable of being fast. A local racer in my club this year put a stock SVT on Kumho 711s (read: crap. He got them for $40 a piece) around the course faster than most of the STi's present, on Azenis or stickier. I asked him what pressures he was running and he shrugged and said "probably something like 30psi, I don't bother checking, its easier to just adjust to the car".
2004 SVT Focus
Custom front-bumper-mount bug guts; precision sprayed brake dust on OEM rims; 15% Pine Tree pollen over the clear coat.
No more SVT autocross, I drive the thing in the avatar.