The initial task is to open up the board by firing specials at the popcorns and the keys. So far, so obvious. But sometimes you will get a board that starts to open up quite easily, sometimes you will get a stubborn board that refuses to yield until it is too late. Sometimes you will get one in-between.
The strategy for a stubborn board is to shrug your shoulders and try again. For a board that opens up quickly and easily, you don not really need strategy, you will get so many special candies and combinations by chance that you would have to work hard not to complete the board in 50 moves.
You only really need to deploy your planning skills for the board that opens up well, but a little late leaving you limited time to complete the task.
One useful strategic point is that you only need one popcorn opening (as long as the keys have opened up that section) to complete the task, but you will probably want to open up more of the board for tempo reasons - i.e. it might be quicker to open up the board than to wait for the conveyor belt to line ingredients up for you. In any case, the board tends to open up quite quickly once it is partially open.
Another helpful point is to save some special candies in helpful places awaiting the arrival of ingredients above drop points. A vertical in the right column can get you all the way through with an ingredient. So you might find yourselves doing some actual counting to work out whether you will get better tempo one way or another.
There is a glitch when creating special candies across two conveyor belts: it is as though one less candy were matched, so that five candies yield a striped candy rather than a colour bomb, and four candies are treated as a regular match.