From top, by Andy Crawford/Getty Images, from Comstock Images/Getty Images, from Creativ Studio Heinemann/Getty Images, by Al Seib/Getty Images.

Don’t try and make your life interesting when it isn’t. Diaries must be brutally honest. If you had only one egg for breakfast, write “Had egg for breakfast.” Don’t feel you have to have had 12 eggs for breakfast just to get in the diary. And leave celebrity diaries to the celebrities. If you don’t know anyone famous, don’t try and pretend you do. “At the airport that Bruce Springsteen’s drummer once used” isn’t good enough. Similarly, “At the hairdresser’s. Saw someone reading about Bruce Springsteen’s drummer” just sounds desperate. On the other hand, “Bruce Springsteen’s drummer is the father of three of my children” is perfectly legitimate.

Even if you are famous, don’t brag about it. There’s nothing worse than a diarist trying too hard to impress. So, avoid “I was the one they were all looking at, but Obama seemed cool with that” or anything like “If I see Angelina Jolie outside the house again I’m going to call the police.” On the other hand, something like “I like goats and they like me” is nice and kooky and quite permissible.

Even if you did babysit for Chuck Berry or neuter one of the Queen’s corgis, it’s much better to just drop it in as a throwaway. As in: “Got up late, made some jam, called the chiropractor, neutered the Queen’s corgi, painted the bathroom.”

Don’t be too obscure. British upper-class diaries are prime examples of this fault, as in Sir Arthur Fforbes-Ffinch’s account of London life in the 1920s: “January 4th: Bo-Bo, Tiggy, Spaff, Flatto, Gin-Gin, Mobbles, and Goofy came round and we all drank Brown Monkeys and played Sham-Sham until we’d crocked Bonzie’s and had to rumble.” Completely inexplicable if you didn’t know it was a Cabinet meeting.

Don’t write anything you might regret. This was an occupational hazard for the great English diarists of the 1930s. “Met Hitler. Rather liked him.” “The Nuremberg Rally could have gone on longer.” “He [Stalin] could go far if he weren’t so pitifully shy.”

Write every day. Diaries are all about habit. They should become a regular part of your day, like cleaning your teeth or going to the lavatory. And, if possible, just as interesting.

Apart from that, the world’s your oyster. As Mae West said: “Keep a diary and it’ll keep you.”

Stalin loved that.