Some more useful tips :
The very best way to avoid food waste is not to buy too much in the first place! So use a menu planner to plan out what meals you will be cooking for the week ahead, and then make your shopping list accordingly.
Don't just eat it - compleat it. Maybe there are bits of fruit and veg you are throwing away that you could actually be eating - here are 8 top tips for compleating
Only cook the amount of food you need - have a look at this portion calculator
If you do overcook, think about freezing your leftovers for another day. Make sure the food is cold before putting it in a sealable container or bag, labelling and putting in the freezer.
Using up leftovers aka Flung Together Food - lots of ideas here.