Being a top groomsman requires more than just looking slick in a suit. Groomsmen are chosen for a reason – to be the dependable, supportive and composed friends that stand by the groom for one of the most significant moments in his life.

So be proud, be suave, and above all, celebrate. Here’s how to do a fine job as a groomsman and make sure the wedding day runs like clockwork.

Wear a new watch. Set five alarms. Arrive an hour early. Do whatever’s necessary so that you (and the groom) are on time to the ceremony. Make sure you know the exact timings of the day, from the wedding breakfast to the speeches. Keep an eye on the clock to help make sure everyone is in the right place at the right time.

You’ll wear a suit that clearly identifies you as a groomsman, so prepare to act as a fountain of knowledge for the guests. As well as timings, get clued up on what’s what and who’s who at the wedding. Questions about seating plans, the bar, the relatives, the toilets… you’ll get asked all sorts, so ensure you know the venue and the guest list like the back of your hand.

In a cool, understated and polite fashion, you’ll need to act as an usher and take guests to their seats for the ceremony. Traditionally, the guests of the bride sit on the left and the groom’s friends and family sit on the right, but this isn’t always the case. Ask the bride and groom beforehand (not on the day!) for any specific instructions, and always be a gentleman when reminding people that the time has come to take a seat. Escort any elderly people, and be sure to give any grandparents a good view.

Everyone aims for a slick, seamless wedding, but chances are there will always be the odd hiccup on the big day. As a groomsman, it’s your job to do whatever it takes to prevent problems, however minor, and help solve them as soon as possible. Ensure that the bride and groom are not affected and are unaware of any potential mishaps, and if it directly involves them, do whatever it takes to make it right. Whatever. It. Takes.

Now’s your time to shine. It’s always a lot more relaxed once the music starts playing, and as a groomsman, you’ll be expected to lead people to the floor and encourage others to dance. Get the party started by grabbing the hand of a bridesmaid, and put aside a moment to share a dance with the bride. Just don’t tread on anyone’s toes…

Above all else, this might be your most important role. First and foremost, you are a friend, and you need to keep the groom calm and composed when he gets the pre-wedding jitters. You’ll also need to do whatever he or his bride ask of you throughout the day. Whether you make him laugh with an anecdote, distract him from getting cold feet, or hand him the tissues if he gets overwhelmed, be the support he needs on his big day.