Level 30 of candy crush is really simple. If you have not learned how to get vertical striped candy yet, then it might be tough. Just focus on mixing 4 candies together by making horizontal moves. This will create the striped candies that will be vertical. Then you can knock of the bottom section.
If possible, put 5 candies together to get a wrapped or a sprinkle, then you can mix those together and knock out more candies. The best combo for this level is putting 2 wrapped candies together. If you can do this, you will be causing the most damage.
Focus on the low part of the board first, this will knock out the frosting quickly and will open the board for getting the ingredients to the bottom. This should be very simple to do once you get the hang of making combos. And if you are not any good at making combos yet, then you are going to have a tough time on later levels. For instance, level 33 is coming up once you get past level 30, and it is 100 times harder. So if you are having issues now, then you are going to get more frustrated.
Good luck crushing level 30!