My Two Cents:

$.01: flying a POS ARF at the contest will be more beneficial than flying nothing.

$.01: as a beginner (I think) myself, the one thing that seems to hurt me the most is when I let the plane get in too close during the sequence, so probably the most important thing I can practice is somehow finding a line and trying to stay on it. It is really difficult to fly gracefully when you've moved in too close and are rushing the maneuvers and have no time for corrections, as well as when you get too far out and can't really see what's going on.