Select the left rollover (P). Seems to be the easiest to consistently hit, and gives you +3x bonus each time, which can result in big points
If you already have a mode started go for the "K" rollover to light multipliers. This teamed with Stay Puft can lead to HUGE points.
Collecting gears using the left ramp, over and over, starts a hurry-up on the proton pack targets (left) which can lead to big points.
In comp. mode, Neg- Re-inforce. will give you a correct guess for every 10 ghosts you have earned. Your very next pick will always be wrong!