Before you worry about spreading the Jam across the upper half of the playing field first spread it across the bottom half. When you’ve covered the bottom half with Jam all the Jelly Fishes you activate will dive at the upper half of the playing field.
With candies of five colors on the playing field you shouldn’t have too many problems making special candies. Still, take your time and don’t miss out on opportunities to make special candies. Consider holding on to special candies until you can combine them because of the combinations’ enhanced effect.
When you activate vertical Striped candies try to activate them in columns without Licorice Swirls. Being able to activate a few vertical Striped candies can make a big difference.
At the edges of the playing there are Jelly Fish Dispensers. Don’t be in a rush to activate the Jelly Fishes that spawn from them. Hold on to them until you can combine two Jelly Fishes.