For anyone browsing Malachain, here is a clear starting point on the subject.
Planning meals for a week takes about twenty minutes once it is a routine. Begin with what is already in the fridge and cupboards, choose four or five dinners that use those ingredients first, and leave one evening for leftovers and one for something spontaneous. Write the shopping list in the order of your local shop and buy only what the plan needs.
The real savings come from overlapping ingredients: half a bunch of herbs for one recipe and the rest for another, one roast that becomes two lunches. After a month compare the receipts with the month before. Most households throw away far less and spend a little less, which is what makes the habit easy to keep going through busier weeks.
If you try any of these ideas, start small and adjust them to your own situation. What works for one person will not suit everyone, and it is fine to keep only the parts that help. Writing down what you changed, and what happened, makes it much easier to see after a few weeks whether the effort was worthwhile.
The most useful step is usually the first one. Pick a single suggestion, try it for a couple of weeks, and then decide whether it is worth keeping. Small, steady improvements last longer than ambitious plans that are hard to maintain once everyday life gets busy again.
It also helps to talk the subject through with friends or colleagues who have tried something similar. Their experience points out the details that guides leave out: how long things really take, which costs were unexpected, and which shortcuts turned out to be a mistake.