Initially, ensure that you release the marmalade-trapped candies as quickly as possible, to ensure that the bottom of the board remains full or nearly full of candy. The marmalade is easy to release - a well-placed, simple three match can release one or even two of these.
Release the locks as quickly as possible. The only way to release them is to make special candies nearby locked ingredients.
Focus on clearing bombs before it is too late, while at the same time bringing down ingredients at one of the right spots - alternate columns - it is hard to switch columns once you have started an ingredient's descent from the conveyor belt, so aim to get this right each time.