There is, of course, no simple answer, though it does help to have people who know what they are doing running the Queen's PR.
Penny Russell-Smith, press secretary to Her Majesty, certainly does that. Last month she produced a list of '80 things you didn't know about the Monarch' and the media just lapped it all up. Penny has also managed to realise that different people want different things from their Queen.
The old farts can enjoy her coming out of Windsor Castle to meet 'her people' as the Grenadier Guards play 'happy birthday', and the kiddies can come to the palace in the summer to meet Bob The Builder, Thomas the Tank Engine and Harry Potter.
The strange thing about the popularity of the Queen is that no one really knows what she's like. Not so strange really when you consider that her mother was even more popular and we knew even less about her. It just goes to show that sometimes in public life, mystery about someone can be a brilliant PR strategy.
I know at least one person in public life who intends to follow the same strategy, and that's the future prime minister's wife Sarah Brown. Sarah realises that if Cherie Blair had opted to strive for a lower profile, she might not be such a hate figure with some sections of the media.
And it is because Prince Charles has meddled too much in politics that he is not nearly as popular as his mother.
She knows to keep her thoughts to herself, while her son writes his all down, with inevitable consequences.
When Gordon Brown said Labour didn't intend to build a new Royal Yacht the Queen was furious. Not because there was to be no new boat – she suffers from sea sickness – but because she read about it first in the Mail on Sunday. Despite her anger though, the Queen knew better than to go public. She wisely stayed silent and it was left to Charles to complain to Tony Blair.
As we watch the Queen's birthday celebrations, think how lucky she is because she has the chance to do it all again in June when she celebrates her 'official' birthday. Her PR team couldn't wish for more.