The Duchess of Cambridge is due to have her baby any day now: diehard royalists are already camped outside the Lindo Wing with only a thermos and a curly sandwich to sustain them, and bookies are laying odds on everything from the newborn's gender, time of birth and most feverishly of all, what name will be bestowed upon it.

As anyone with a bump will tell you, one of the few pleasures of pregnancy is whiling away four zillion hours contemplating baby names - from the adventurous to the downright ludicrous. Quite possibly, the Duke and Duchess are obsessively trawling the Mumsnet baby name finder as I write - let's hope so because there are potential pitfalls at every turn when it comes to baby names and lots to bear in mind.

Many parents are understandably keen to find a 'unique' name, but this approach can be fraught with difficulty. Names are as much subject to the vagaries of fashion as anything else - and it's often hard to see those vagaries at work. Many, many parents alighted on a name which feels progressive and fresh - only to discover that thousands of others have quite simultaneously come up with precisely the same unique idea.

A friend of mine is still outraged, fourteen years on, that the name Oscar - which she swears she'd never even heard spoken aloud until she gave it to her precious first born - was, by the time he was four months old, ringing out across every baby music class in the land. Lily and Alfie similarly seemed to become ubiquitous overnight. If this has happened to you, console yourself with the thought that these are all excellent names; the fact that there are three others in Reception - or indeed amongst your immediate family circle - doesn't change that one jot.

In the hope of avoiding this situation, some parents are tempted to go too far in the other direction. The Mumsnet forums are awash with mothers-to-be asking if they're being unreasonable to name their precious first born Mimsy Bonnet or the like, and being utterly astonished when the crowd-sourced answer comes back a resounding 'Um, yes.'

The prevailing advice when considering a slightly outré name, is to consider whether it would still work if the child in question became a High Court Judge. The law has certainly become more liberal over the decades, but I'd say Her Honour Mimsy Bonnet is unlikely to grace the benches any time soon. And don't, for peat's sake, fudge it by opting for a classic name with an 'interesting' spelling: this is the worst of both worlds and will consign your child to a lifetime of correcting people's spelling. Recent examples include Daniol, a Naiphthan, a Caytie and and Alivia.

Infographics can be a great help when deciding baby names - but the pitfalls of choices like Naipthan and Wolfgang should really be self-evident. ONS

Since this is their second time around, the royal couple will, with luck, already know each others' limits. Just as well: picking out a baby name is one of the first choices that couples make together as parents - and quite likely the first parenting decision they will argue about. Many Mumsnetters are most indignant when they discover that their partners are expecting to have an equal (or any) say into the naming of the forthcoming child, especially considering they tend to hide behind a veil of apathy for the entire pregnancy - only to decide, the minute the babe is born, that they're rather taken with the name of an ex-girlfriend. No chance, matey.

If you and your other half simply cannot agree, the sensible approach is for one party to draw up a longish list of names they like, and let the other choose. If you're desperate for a particular name, you are perfectly within your rights to be ruthless here by surrounding it with unlikely contenders, thus: "Wolfgang; Fly; Thomas; Spongebob; Kermit". Thomas it is, then. If that fails, agree in advance that the parent - I'm not saying which, as that would be sexist - who has endured three days of agonising labour should have the casting vote.

If your partner is determined to honour Great Aunt Hypatia, try to hide it somewhere in the middle. Middle names are the graveyard where ugly family names go to die - or rather to be cryogenically preserved until a future generation finds them alluring again. And if you have any entertaining frivolous names you love but don't quite have the cojones for, bung them in as well. Do take care over initials though: "'Alex Samuel Benjamin Oliver sounds lovely," points out one wise Mumsnetter, "but spells out ASBO." That's not going to look good on the monogrammed china, should the baby eventually hit the big time.

Justine Roberts is founder and chief executive of Mumsnet and Gransnet. She has also sat on the Expert Steering Group on Family Support Services, the Consultative Council of the British Board of Film Classification and the Commission on Civil Society and Democratic Engagement.

You can find her own Twitter @Justine_Roberts, or visit the Mumsnet page @MumsnetTowers. Alternatively, for all information about Mumsnet please visit the website here.

On 16 May Mumsnet is holding its annual Workfest event in London, featuring talks from the likes of Jo Swinson MP, Shami Chakrabarti and Anabel Karmel MBE. For more information please visit the website here.