Choose food that is happy at room temperature

The single biggest favour you can do yourself is to build the menu around dishes that taste just as good after an hour on the table. Anything that needs to be piping hot, or that wilts the moment it leaves the fridge, will have you running back and forth to the kitchen instead of sitting down with your friends.

Think in terms of generous sharing plates. A whole roast chicken jointed into pieces, a salmon fillet baked in foil and served cold with lemon, or a slow-roasted shoulder of lamb that pulls apart with a fork all work beautifully. Around that, add two or three substantial salads: new potatoes tossed with mint, butter and a little crème fraîche while still warm; a platter of tomatoes with torn mozzarella and basil; roasted courgette and pepper with garlic and olive oil. A bowl of butterbeans with red onion and parsley costs almost nothing and improves as it sits.

Then add things that need no cooking at all. Good bread, a wedge of cheese, a dish of olives, a pot of hummus, sliced ham, a jar of pickles. If you want a pudding, keep it simple and sturdy: a Victoria sponge, a tray of brownies, or a bowl of strawberries with a jug of cream.

• Dress leafy salads at the very last minute and keep the dressing in a jar beside the bowl.
• Undercook pasta salads slightly — they soften as they absorb dressing.
• Keep mayonnaise-based dishes out of the sun and don't leave them out for more than two hours.
• Write a simple note for each dish if anyone has allergies, so nobody has to ask.

Set a table that will not wobble or take off

A lawn is rarely level, and a flimsy folding table on grass is a disaster waiting to happen with a full jug of water on top. Use the sturdiest table you own — a proper trestle, a heavy garden table, or two smaller tables pushed together and clamped. If one leg sits low, slide a flat piece of wood or a folded beer mat underneath until it is rock solid. Test it by leaning on each corner.

Linen tablecloths look lovely but flap about in a breeze. Either use clips, or choose a heavyweight cotton cloth, or skip it entirely and use a wipeable table top with a runner down the middle. Avoid tall centrepieces: people want to see each other across the table, not peer around a vase of sunflowers. Low bowls of herbs, a few small candles in jam jars, or a single jug of flowers will do.

Check your seating too. Mixing dining chairs with a garden bench is fine, but make sure everyone has somewhere proper to sit and that there is at least one spare chair for the person who inevitably brings a partner or a neighbour.

Sort out shade before anyone arrives

Work out where the sun will be at one o'clock, at three o'clock and at five o'clock. A table that is perfectly shaded when you set it may be in full glare by the time pudding appears. A parasol with a weighted base is the easiest answer, but a simple sail shade strung between a fence post and a tree, or a pop-up gazebo, will do the job just as well.

Do not put the table directly under a tree unless you enjoy wiping sap off plates and picking leaves out of the salad. A spot just beside the canopy is better: dappled light, no debris.

Have sun cream in a basket by the door, plus a few hats, and keep a light blanket folded nearby for when the afternoon cools. If wasps are a problem, set a jam jar trap with a little water and sugar at the far end of the garden, well away from where people are eating — never on the table itself.

Let guests help themselves

Self-service only works if everything is genuinely within reach and the order makes sense. Lay it out in the sequence people will use it: a stack of plates first, then the main dishes, then the salads and bread, then cutlery in jars at the end so people are not juggling a fork while trying to spoon out potatoes.

Put the drinks in a completely separate spot, ideally a small table or a sturdy tray on a bench a few metres away. This stops a queue forming at the food and gives people a reason to move about and chat. A cool box with ice, a jug of water with lemon and mint, and a bottle of something fizzy are all you need.

Top up dishes quietly as they empty rather than bringing everything out at once, and keep a spare plate or two of each dish in the kitchen so nothing runs out at the wrong moment. If someone offers to help, say yes — let them carry the bread or open the wine. It makes them feel part of it.

Then sit down and enjoy it

The best garden lunches are the ones where the host is not continually jumping up. Once the food is out and the drinks are poured, take your own seat, plate in hand, and let the afternoon unfold at its own pace. Nobody minds if the salad bowl is in the wrong place. They will remember the long, unhurried hours under the trees, the second helping of potatoes, and the fact that you were actually there with them.

Keep the washing-up for later. It will still be there, and the light in the garden at six o'clock is far too good to waste.