Have you tried batch cooking? It can make things a lot easier, so things like casseroles and chilli etc.
Another thing to try is to buy a big pack of mince when it's on offer, chop a few onions and fry, then fry off the mince. Cool and freeze it and you have the basis of a bolognaise or lasagne, chilli, cottage pie or whatever.
I like to do time intensive things in bulk, so for example I buy a block of cheese and grate the lot in my processor, then put in a resealable bag as most of my use for cheese needs to to be grated.
I do a large bag of chopped onions in one go and freeze in smaller bags. A stinky job that can put you off starting a meal.
For your store cupboard, keep a stock of pasta, rice and noodles. Noodles are very quick to cook and you can chuck in meat/veg or whatever you like. I keep stock cubes, spices and herbs, Worcester sauce, soy sauce, balsamic vinegar as staples.
I waste very little and I keep a tray of leftovers in the freezer for such meals. For example leftover chicken and ham, peppers and onions, salami. These little bits also make great pizza toppings and if I open a tin of pineapple, I freeze the rest for a Hawaiian pizza.
Bags of frozen veg are very helpful - I have peas, peppers and sweetcorn.
If you have lemons, limes or oranges on the turn, cut them up and freeze them to add to drinks as flavoured ice cubes.
Eggs are good - omelettes in minutes especially if you have the "leftovers" tray in the freezer.
That was a waffle but hope it gives you some ideas 