The most fragile of wedding day rituals, more often than not a best man's speech is considered a success as long as it's not a total, flaming, marquee-silencing catastrophe that pays homage to every excruciating detail of the groom's past and ends with that "Bangor" honeymoon joke...

You know the one.

But what if - and bear with us here - what if rather than winging the speech off the back of a bottle of table wine, our nation's Best Men stepped up and put a little effort into their moment on the mic?

With that in mind, we reached out to Oliver Lucas, a professional speechwriter and the owner of iamthebestman.co.uk, to give us the rundown on how not to ruin your best mate's big day.

Here's a tip: never liken the bride to a dog.

You get that one for free.

Do | Prepare

"People may not realise it," says Oliver. "But in some ways a best man speech is like performing on stage. It takes time to really perfect the performance, and it's never going to be right first time."

"Actors and comedians don't just rock up and give great accounts of themselves on the first show. They take the time to perfect their art - best, best men do the same."

Don't | Wing It

Relating to the above point, it's a rare kind of man who can stand up in front of potentially hundreds of people and deliver an impromptu speech. "I've seen many shocking best men speeches", says Oliver. "But two of the worst that spring to mind were when the speakers fancied their chances at 'winging it'. Sadly, it's just not that easy." (see Prepare above.)

Do | Say it out loud

According to Oliver, "The absolute minimum that any best man should do is to say their best man speech out loud three times before the showtime." Adding that "Many only do so on the day for the first time and are surprised when things sound differently than it did in their head."

Don't | Assassinate the groom

Give your friend a bit of a hard time about the stag do? Sure. But to go off on a ten minute diatribe centred on his deepest fears and failures is, in the words of Oliver, "not cool."

Here are his rules for avoiding being the dickhead that your friend's parents can't look in the eye after dinner.

1.) Would grandparents find it amusing?

2.) Has the material been run past a select group of family and friends and received their approval?

"If the answer to either is 'no', then said material should be excluded", says Oliver.

Do | Include the bride

While it might be the best man's speech, let's not forget that the day also involves the person he's marrying. "This doesn't just mean a cursory comment about her physical appearance (which in of itself can sometimes sound quite patronising)", says Oliver. "But is more about who she is, and the obviously important role she has played in the groom's life."

And please, no dog jokes.

Don't | Go On Too Long

According to Oliver, this is a common mistake for first time best men, and inexperienced public speakers. "Here's the thing to remember - whilst it's true that the best man's speech is considered 'the entertainment', the audience will have sat through two, or more, speeches before this point and therefore their attention span will be starting to dip."

"A best man speech needs to be no more than 10 minutes, some recommend as little as five. Either way, keep it punchy."

Do | Get Feedback

Says Oliver, "Feedback helps shape and hone the delivery, but critically, it can also identify and remove any material that is likely to bomb, or worse still, offend people."

Don't | Mention money, sex, politics, exes or religion

Even if the groom is totally fine with you discussing his bank balance and previous flings (unlikely), that doesn't mean everyone else will be quite so chilled (see the grandparent rule).

Be sensitive.

Do | Add a little sincerity

"The best man has been selected because there is a deep level of trust, friendship and dare I say, love between the two", says Oliver. "So in amongst the jokes and the anecdotes, there should be some sincerity. Best men should not miss the opportunity to recognise the friendship and the importance of it in their own lives."

"I think we're all modern enough men not to let that go unspoken."

And if all that still doesn't work, you can always give Oliver a call to write one for you.

Good luck out there.