Store Food Correctly
First and foremost, food should be stored correctly. Improper storage can easily become the victims of pre-mature ripening, leading to spoiled produce. Certain vegetables, like onions, tomatoes, garlic, cucumber and potatoes should be kept at room temperature, while the spices should be stored inside airtight containers.
Fruits like banana, avocado and mango produce high contents of ethylene gas as a part of the ripening process, and therefore, they should be stored separately from the ones that don't produce ethylene. Because keeping them together can spoil the latter.
Learn About Food Preservation Methods
While extending the shelf life, preserving techniques can add an extra layer of flavour to certain food. The excess lime, mango and fish can be preserved by salting and drying, which creates some amazing rice pullers like lunu dehi (salted lime), lunu amba (salted mango) and karawala (dried fish). Another way of preserving fish would be jaadi; something that's very popular among the Southerners. All you need is some goraka (Malabar tamarind) and salt to whip up this one.
Meats can be smoked or dipped in bee honey, like Veddahs do, while fruits can be easily preserved by sugaring (jam and chutney etc.). If you've got some milk that's on the verge of going bad, make some homemade yoghurt or curd with it.
Many a fruit/vegetable can be pickled, and seeds can have a long life under the dry sand. Have a look at this article if you want to know how each of these methods stretches the shelf life of food.
An Organised Fridge
Having a well-stocked fridge is a good thing at times like this, but you need to make sure that it's properly organised and not cluttered. Use the FIFO method; First in First out to systemise your fridge. When you buy new food items, make sure to place them at the back of the fridge while leaving the existing ones at the front, so it would make sure that you consume them first. That way, they won't be spoiled, or go to waste.
Include eating leftover food in your weekly meal plan. You don't have to eat them as they are, but try to add them to the usual dishes you make. For example, if there's leftover rice, toss it into the pan along with a few veggies, an egg, and spices and you get yourself some yummy fried rice. It's easy to make, requires minimal ingredients, delicious, and frankly, you don't need to bother about making curries to accompany this one.
Get Creative in the Kitchen
Let's say that you have a bunch of veggies that are about to go bad. Why not toss in all of them together and create something "one-pot"? One-Pot soups, one-pot stir-fry and one-pot pasta; the internet is filled with these recipes. Add a bit of twist to them, let the kitchen be your creative space and try to craft up something with the ingredients you have.
Think of it this way; keeping an eye on the serving size of your food is also a way of watching your figure. Observe how much food you throw out today and based on that, reduce the portion sizes and ingredients you pick to cook tomorrow. While minimising the food waste, this would help you eat healthy as well.
By boiling the excess vegetables, peels, scraps, and bones, you can make homemade broths, and later use them as the base of some delicious soups or to cook rice with. They don't take much of a space in the fridge too.