Add few drops of glycerine while beating the cake batter to make it spongier and softer.
Add a piece of coconut while making a yogurt at home. It will remain fresh for 3-4 days.
Add a little lemon juice in the gram flour while making a batter for pakodas to make it crisp and less oily. Similarly, you can add rice flour also.
Remove the stem of green chilli, put into a plastic container and store it into freezer to preserve it for more days. This retains the freshness of the chilli.