A good shopping list is not a wish list. It is the bridge between the meals you have decided to cook and the food that actually ends up in your kitchen. Get it right and you spend less, waste less, and cook more of what you planned. Get it wrong and you come home with three bags of shopping and nothing that makes a dinner. The trick is to build the list in a fixed order, so nothing slips through.

Start With the Plan, Not the Cupboards

Write your meal plan first, even if it is only five or six dinners scrawled on the back of an envelope. Be realistic about the week ahead: if Tuesday is a late finish, that is not the night for a slow-cooked ragu. Note which meals are for which day, and jot the odd lunch or breakfast idea alongside if you know you will need it.

Now turn each meal into its parts. A traybake of sausages, red onion, peppers and potatoes reads as four items. A curry night reads as onions, garlic, ginger, a tin of tomatoes, coconut milk and whatever protein you fancy. Do this for every meal before you write a single item on the list proper. It feels slow the first time and takes about ten minutes; it saves you a second trip to the shop, which is never ten minutes.

Group repeats as you go. If three meals this week need onions, you do not need to note them three times — you need to know whether one net or two will cover it.

Audit the Fridge, Freezer and Pantry

Before you decide what to buy, find out what you already own. This is the step most people skip, and it is the one that quietly saves the most money.

• Fridge: check dates and pull anything that needs eating soon to the front. If the spinach is on its last day, either move a meal forward or add spinach to something else.
• Freezer: a quick rummage for peas, prawns, a tub of leftover chilli, frozen berries. Half of a planned meal may already be in there.
• Pantry and cupboards: rice, pasta, tins of beans and tomatoes, stock cubes, spices, oil, flour. You are checking both whether you have it and whether you have enough of it — a tablespoon of rice is not dinner.
• Perishables you assumed were there: milk, butter, eggs, bread. These catch people out every week.

Anything you find that is already covered gets crossed off the list you are about to write. This is why the audit comes second and the written list comes third.

Write the List by Supermarket Section

Now write the real list, but organise it the way you actually walk the shop rather than the way you thought of the meals. A typical route looks something like this:

• Fruit and veg — onions, carrots, peppers, potatoes, lemons, fresh herbs, salad
• Bakery — bread, wraps, the odd treat
• Meat, fish and deli — mince, chicken thighs, sausages, bacon
• Dairy and chilled — milk, butter, cheese, yoghurt, cream, eggs
• Tins, jars and dry goods — chopped tomatoes, chickpeas, coconut milk, pasta, rice, oil, spices
• Frozen — peas, chips, fish fingers, fruit
• Household and toiletries — only if genuinely needed

Writing in this order sounds fussy but it is the single best defence against impulse buys. You stop criss-crossing the shop, you stop doubling back for the thing you forgot, and you stop drifting down aisles where nothing on your list lives. Add rough quantities next to each item — 2 onions, 500g mince, 1 tin coconut milk — so you are not guessing in the aisle with a trolley in one hand.

Plan for the Extras You Will Actually Need

A meal plan rarely covers every bite of a week. Build in a small, honest allowance for the things that make cooking easier:

• Lunch basics: bread, cheese, hummus, a bag of salad, tinned soup
• Breakfast restocks if you are running low
• One or two freezer backstops for the night everything goes wrong
• Storecupboard top-ups that are nearly out — oil, salt, stock cubes, coffee

Being honest about these now stops them becoming an emergency mid-week shop where you buy half the aisle. It also helps to shop your plan in date order: cook the fresh fish early in the week and leave the freezer meal for Friday, so nothing wilts in the bottom drawer.

Keep the List Working After You Get Home

Put the shopping away with the plan in mind. Keep the ingredients for the first couple of meals together and visible, and put the longer-life items behind them. Stick the meal plan on the fridge where everyone can see it — it heads off the there's nothing in conversation before it starts.

Finally, keep the list for a week or two. A glance back shows you what you bought and never used, which is the most useful information you will get all month. Adjust, and the next list will be sharper than the last.