1. You may think this is as much your day as your wife's. It's kinda more 70/30 in her favour. Scratch that ........80/20.  
In all seriousness, the day belongs to both of you and there's no better feeling than seeing your beautiful wife enjoying the day.  There is an old saying. "Happy wife, happy life"......... I'm saying nothing more.

2. Choose your best man carefully.  If they've known you a long time chances are they'll have at least a few stories that could raise an eyebrow with the new in-laws and at worst will have you having to answer some hairy questions from your new betrothed.  If at all worried discuss this with your best man beforehand and agree some NO-GO areas.  

3. Write a speech. No seriously I mean really write a speech - write it down. Include bride and bridesmaids look beautiful, thank all those that have contributed towards the wedding, include an amusing but not embarrassing anecdote about your new wife, mention how thankful you are to be part of a her family etc, think about all the things you've heard before at wedding speeches............ and immediately discard the cliched.  Remember to say the best man is prone to making things up - people expect that.  Above all take your time, take a deep breath, look up at people and make eye contact. Don't be afraid of the dramatic pause, silence isn't necessarily a bad thing and can draw people into your speech. Once it's over and done with relax.  Never worry about what could have happened once it's over.

4. Your day will be over in a flash so,  take time to enjoy it.  The day will fly past you if you let it.  Spend time talking to friends and family but remember they are there to see you.  Do keep coming back to your wife, see how she is etc.  Take time to check out the little things that you both have planned as well as make sure you compliment anyone who's helped you make the day special.  Spend time with the photographer getting great photos - in 20 years they are all you will have after the cake has gone and the flowers have died the memories fade so be patient and get the shots.

5. Get involved with the planning, even if it's just choosing the band.  Do it. Commit to it.  Too many times I hear "thanks to my wife who has planned the whole thing etc etc" The day should be a reflection of you both as a couple so put your spin on it.

Thanks for listening be sure to subscribe 

Peter