In sailing, you'll usually want to actually clear boards at first. Don't aim for combos above double or triple. Then, once your duty indicator is -already- at least light yellow (maybe not sparkling), that's when you start working on the real combos. It's sad to booch a puzzle for a league because you never actually cleared something you were so combo-hungry!
Also, in Rumble, some quick tips on the amount of stuff generated.
For sprinkles (non-charged stuff), each cleared group adds to a queue that slowly builds up, and there is NO difference between clearing three groups of four each, and one group of twelve. (Although you send sprinkles equal to half the cleared balls, so 3 is quite sub-optimal while higher numbers are better.) Loose stuff that gets dropped when you clear a group sends its number divided by three--fractions discarded, again--so aim for a multiple of three if you can help it! A big take-away hint here, though, is: If you can clear groups as fast as you can click, then clear groups, don't build up random crap to drop. However, if you have a great shot sitting on your right launcher, and you're still looking for your next play, feel free to build up droppable stuff as fast as you can click with your left launcher as long as you won't blow your shot.
Don't send charged strikes with less than three groups together--that's the minimum to actually punch the guy. Weak strikes are often enough to mess with someone pretty hard though, and in general each dropoff ball will give you another bruise in your punch...so feel extra free to pile dropoffs onto your combo before you set it off!
And try to keep your playing field as flat as possible. It makes sprinkles MUCH easier to annihilate in a couple shots.