The quietest hour is early morning, when locals are out exercising and the promenade is close to empty, though the historic facades are flat in that light and the lights across the river have already gone off. The busiest hour is the one after sunset, when the skyline lights come on and the crowd peaks at the same moment, with weekends and public holidays worse still. Fewest people and best light are not the same answer; confirm the day's lighting and event schedule before you go.

The Wukang Building is an old apartment block on the wedge of land where two roads split in the former French Concession, designed in the 1920s by a well-known architect of the period, with its narrow end facing the junction so that the whole flat-iron outline reads in one frame from the opposite pavement. It is photographed so heavily because the corner composes well, the plane trees change with the season, the surrounding streets are full of old buildings, and its reputation has fed on itself online; the cost is a crowded pavement at peak times on a block where people still live. For the architecture and the streets it is worth a deliberate trip; for a single social-media photograph the experience is usually worse than the picture.

The name Yu Garden covers two places in Shanghai: the Ming-dynasty classical garden inside the wall, which is ticketed, and the bazaar and old-city streets outside it, which are free and open to anyone, and most of the Yu Garden photographs people take are taken outside the wall. Whether it is worth going in depends on what you want: anyone interested in the garden and historic architecture itself should pay, while anyone mainly after the bazaar, the food and photographs of the buildings will miss little by staying outside. The price, whether a reservation is required and whether entry is sold in timed slots keep changing, so confirm the day's arrangements through official channels before you go.

Sort what counts as near Shanghai into three different things first: the Jiangnan water towns around the city, garden cities such as Suzhou and Hangzhou, and the outer parts of Shanghai municipality itself. Which of those three you want matters more than which destination you pick. Suzhou and Hangzhou are each worth more than a day, so a day trip to either is a compromise, and you should check the last train back before you commit.

It depends on the kind of place: the well-known museums, galleries, anything with a capacity limit and the resident shows are mostly sold by date and time slot now, and without a booking you may well not get in that day, while parks, the riverside, shopping streets, most neighbourhoods and the temples and gardens that sell at the gate need nothing booked at all, which is most of a Shanghai trip. So the only things to arrange ahead are the two or three you would be sorry to miss, confirmed through each venue's own channel, and the rules keep changing.

What Shanghai offers photographs falls into roughly eight kinds: the skyline across the river, the historic waterfront facades, the old-city lanes, the plane-tree streets of 1920s and 1930s houses, the converted industrial sites, the classical gardens, ordinary residential streets and the night illumination, and each works under different conditions, so decide which kind of photograph you want before deciding where to go. By volume the riverside skyline is the most photographed and least informative single picture in the city, and the photographs that hold up usually come from a street, a lane or a building detail. The useful light is the stretch after sunrise and the stretch before sunset, the timing shifts a long way across the year so check the day's times before setting out, and the care owed to people you photograph, the limits on official buildings and the restrictions on drones are worth knowing in advance.

Yes, considerably, and the difference is not marginal: the same sight during a holiday and again once the holiday is over are two different experiences. Spring Festival and the National Day holiday are the sharpest, with the summer school holidays and the spring and early-summer holidays behind them. If you can move your dates, move them; if you cannot, change the shape of the day, setting out early, spending the middle of it indoors or away from the centre, booking timed-entry venues ahead and taking the metro instead of a car.

Yes, for some travellers, and only once you know whether you are going to a preserved town or one rebuilt to look like one. A preserved town is a place that grew; a rebuilt one was constructed to resemble it, and photographs rarely tell them apart. Pick the right kind and stay until the crowds leave, and the day holds up.

Whether it is worth going up depends entirely on what you want from it: if you want the city view, the tower is the weakest way to get one, because from up there you cannot see the tower itself and the best view of it is from the far bank; if you want to stand on a glass floor once, take children up somewhere high, or be inside the building on every postcard, it holds up. The one thing to check before buying is whether the air is clear that day, because on a hazy day the time and the money buy a band of fog.