Concentrate on the spinner and the two saucers in the top left.
If ball runs the gauntlet all the way down to far right lane, be prepared to give the cabinet a whack on the right side to save the ball!
"Mystery bonus advance" is always 1 to 3 advances. If you see the third advance, be ready for the ball to return to play!
The bonus maxes out at 10,000 (indicated by the balls on the backbox). At this point, it would be wise to collect and build again!