Car boot sales are less a shopping trip than a treasure hunt with weather attached. The good stuff is rarely arranged prettily at the front of a pitch; it is in a box under the pasting table, behind three DVD players and a broken strimmer, and it will be gone by half past nine.

Knowing when to go, when to arrive and how to behave once you are through the gate counts for more than luck. Here is how the season works, and how to work it.

When the British boot season actually runs

The season broadly stretches from Easter to the end of October, with the fat of it between May and September. That said, the edges of the season are often the most interesting. Early sales in April and May are full of lofts and garages that have finally been emptied. Late sales in September and October are full of people who cannot face storing it all for another winter.

Winter does not stop the hunt so much as move it indoors: indoor boot fairs, flea markets, small collectors' fairs and saleroom viewing days. Use those months to learn hallmarks, backstamps and maker's marks, so that come spring you can recognise things quickly rather than squinting at them in a field.

Bank holiday weekends are the busiest of all. They are also the days when the field is thick with dealers by seven in the morning, so if you want first pick, plan around them rather than for them.

What each part of the season gives you

April and May: the clear-out

Fresh stock, and sellers who have not yet decided what anything is worth. Rain is your friend here: a damp forecast thins the crowd considerably, though it also keeps some sellers at home. Turn up and take the chance.

June to August: volume, and competition

Bigger fields, more pitches, more buyers. The best material tends to surface early rather than late, and the toy, book and tool hunters are out in force. This is the time to arrive before opening and to walk rather than browse.

September and October: the softening

End-of-season pitches often carry things that have been dragged out every weekend since May. Sellers are tired and prices loosen, especially on bulky items in the last hour. This is the best window for furniture, tools and anything awkward to carry home.

November to March: indoors

Indoor fairs, auction viewing days and the specialist fairs that cluster through the winter. Fewer finds, better research, and a good chance to chat with people who know more than you do.

Read the pitch before you buy

A pitch tells you a great deal in ten seconds. House clearances come in mixed boxes, often unsorted and unpriced. Dealer pitches are tidy and priced; you will pay more, but the sellers often know what they are talking about, and a conversation can be worth the premium. Family pitches — a parent and child selling toys, books and outgrown clothes — are usually the cheapest and the least picked over.

Look underneath, not just at eye level. Boxes under tables, behind the stall and in the open boot of the car are where the unsorted material lives. Ask, politely, whether you can have a look through them. Most people say yes.

Early-bird tactics that work

• Check the opening time, and whether the sale runs a paid early-entry hour. Some do; most do not, and turning up at dawn to a gate that opens at eight is just standing in a field.
• Walk the whole site fast before you buy anything. It stops you spending your budget on the third pitch and regretting it at the fortieth.
• Go back to the pitches you liked. What looked like nothing at eight often looks like something at ten, once the top layer has sold.
• Carry cash in small notes and coins. Plenty of pitches are cash only, and a seller with no change is a seller who will not budge.
• Keep a torch in your pocket early and late in the season, and a folding trolley or crate in the boot for anything heavy.
• Ask direct questions. "Do you have any old tools?" or "Anything left from the house clearance?" works far better than silent rummaging.
• Leave your name and number with sellers who deal in what you collect. Regulars get first look at the good boxes.

Etiquette that pays off

Boot sale manners are simple, and they matter more than most buyers realise. People who behave well get shown the box that was never put on display.

• Ask before you handle a stall's stock, and put things back roughly where you found them.
• If you break it, you buy it. That is the unwritten rule, and many sites have a sign saying so.
• Do not haggle over a 50p item. Bundle instead: "Would you take a pound for these three?"
• Step aside when someone is browsing behind you, and do not block a pitch while you decide.
• Keep bags in front of you in a crowd, and do not lean over other people's shoulders to reach.
• Ask before photographing a stall, and never photograph somebody's child.
• Do not try to buy things that are plainly not for sale — the chair the seller is sitting on, the pram, the dog.

Haggling is expected on larger items, but do it with a smile and a real figure rather than a lowball. Sellers remember faces across a season, and being remembered well is worth more than the fifty pence you shaved off.

After the field: what to do with your finds

Before you clean anything, look it up. Over-enthusiastic polishing has stripped more value from brass, silver plate and old furniture than honest dirt ever did. Keep a note of what you paid and where you bought it; provenance matters later if you ever sell, and it is surprising how quickly you forget which field a thing came from.

Check timber for woodworm holes and textiles for damp or moth before they go into the house. A few days in a cool, dry room, a soft brush and some patience will do more good than a strong chemical. If something looks genuinely significant, take it to an auction house or a specialist valuer rather than trusting an online forum. And if you intend to spend seriously, treat it as discretionary spending and set a limit before you go.

Before you set the alarm

Pick your field, check the forecast, and check the sale's own opening time rather than a directory's. Take cash, layers, a bag you can carry all morning and a short list of three or four things you are genuinely looking for. A list keeps you focused; the rest of the field will supply the surprises.

And if the weather looks grim, go anyway. The traders who stayed at home are exactly the ones who would have outbid you.

Photo: jarmoluk / Pixabay