As level 756 is timed, you cannot waste any second making matches there! Matched a few pieces, and now new ones take their time falling down? Don’t wait for them – play in a different part of the field. Don’t see any matches near the tiles you were trying to destroy? Turn your attention to a different area. This way you won’t waste any time and will easily get through the level.
Keep a close eye on the field, as it is essential that you do not miss a chance to create more power-ups! Do not rush into using them though – try to get a couple of power-ups close to each other and activate them in a single move. This will clear more space and will charge the Lightning power-up faster.
Match pieces near the bottom of the game field (or as low as possible) as often as you can. Doing this will shift the largest amount of pieces and start a chain reaction that will create new opportunities to make power-ups.