Level 75 is one of the hardest levels in Candy Crush Soda Saga game, although it has recently been updated to remove some of the layers from the blockers it is still hard to complete. The reason is that you cannot complete the level by making matches next to the chocolate and moving down the board.
At the beginning the space you have to make matches is small, and there aren’t more options with so many colors of candies on the board. You have to clear out space as quickly as possible to get more opportunities to make combos later in the level. Try to make matches next to the chocolate to stop it from spreading. Focus on destroying Chocolate and Cupcakes to make some spaces, and try to find the best possible choice on each match. If possible make matches that will directly remove the chocolate.
When half the playing field is cleared you should start to plan combos. Try to create special candies and combine them, and it is okay to let the chocolate grow while working on setting up combos, a big combo will be much more valuable than stopping the chocolate from spreading.
Try to find places where you can set up big special candy matches, big combos include color bomb or coloring candy + fish, striped or wrapped candy, and combos with coloring candies or color bombs matched together or with each other.
If possible creating a Fish candy, you do that by matching 4 candies together to form a square. Although a Fish candy only removes one object, they tend to remove an important piece from the playing field such as a Bear, a Bottle, Chocolate, Honey etc.
Striped and wrapped candy combos can be very helpful. They could clear a massive section of the upper level and up to 3 jellies in the lower section.
The best method to make more points is to complete the level as quickly as possible, because this will earn you bonus points for the sugar crush, and to use special combinations. Try putting together a chocolate ball and combine it with any other special candy, this will earn you more points.