Edinburgh Castle opens at 9:30am. Be there.

The castle sits on a 130-metre volcanic plug in the middle of the city. That geological fact matters because it means there is one road in, one gate, and one queue — and on a summer morning without a pre-booked ticket that queue is 45 to 90 minutes before you even see the Crown Jewels. With a skip-the-line ticket you go through the dedicated lane. You are inside, looking at the oldest crown jewels in the British Isles, while other people are still working out which queue they’re in.

Give the castle at least three hours. Most people underestimate it. The Scottish Crown Jewels, the Stone of Destiny, the Great Hall, the National War Museum, the views from the battlements — it is a substantial half-day.

What else is worth booking in advance

Real Mary King’s Close — Underneath the Royal Mile, sealed since the 17th century, sits a network of closes and rooms that look like the century they were abandoned in. Guided tours only, group sizes limited, tickets sell out. This is not one you can decide on the day. Book before you arrive.

Scotch Whisky Experience — At the top of the Royal Mile, next to the castle. Guided tours cover all five Scotch whisky regions with tastings. Worth doing in the first evening rather than competing with sightseeing time. Pre-booking gets you your preferred time slot and skips the desk queue.

Holyrood Palace — The monarch’s official Scottish residence sits at the bottom of the Royal Mile under the crags of Arthur’s Seat. The room where Mary Queen of Scots watched her secretary get stabbed is in there. Pre-book from June to September.

Two things that cost nothing and are worth your time

Arthur’s Seat. The extinct volcano in Holyrood Park, 251 metres above sea level. The walk to the summit takes about 45 minutes and the views across Edinburgh, the Firth of Forth and the surrounding hills are among the best in Britain. Free. Always open. Do it on a clear afternoon after your ticketed morning attractions.

The National Museum of Scotland on Chambers Street. Free entry, world-class collection, genuinely excellent. Particularly good if the weather turns, which in Edinburgh it sometimes does.

One more thing: if you are visiting in August, Edinburgh during the Fringe is one of the best experiences in Europe — and one of the most logistically demanding. Book accommodation and castle tickets at least 6 weeks ahead. The entire city fills up in a way that is difficult to describe until you have experienced it.