On ball 1, I like to start a scene so I don't have to hit Slimer and can use him to re-light modes on ball 2 while taking the 5x bonus skill shot. On ball 3, I might take a start mode skill shot if I am close to finishing a mode and don't want to risk Slimer, but that 5x is big, and you often will collect hold bonus in the pops on ball 3 as a random award.
Beyond skill shots, modes are where your points lie. If you're in a mode, focus on finishing it. Draining is bad in any game, but dropping out of a mode because you tried to pick up a hurry up (Slime award, Terror Dog) and draining really kills your momentum.
You can get HUGE points if you have playfield multipliers going and get into multiball with a mode going and Loopin' Supers.
Wait, forget everything I said and just crush it on a built up Loopin' Supers (have to collect 60 ghosts to start) with a playfield multiplier active.