Make sure your uncle gets so drunk that he heckles the ceremony. Also make sure that childless friend complains loudly about how child friendly your wedding is. Have bridesmaids, with no warning, do a song and dance routine that makes your DH sit there shaking his head, and make sure this is captured on any videos people take so that said bridesmaids can't be shown.
Reluctantly decide to have a gift list, even though you hate asking for presents, and spend hours choosing nice cheap presents that will, however be really useful (tea strainer, oven glove, etc). All but three of the guests will ignore this and buy you towels or hideous lamps. Even after ringing you to ask what exactly off the list you would like, just to put you on the spot and make you feel awkward.
Spend ages ringing round bus companies to get a cheap bus from your old hometown and back again for the 30+ guests who say they would like this. NOT ONE will actually want it in the end.
Make sure your FIL disapears for hours on end, with no mobile, with your perfectly happy baby, so she isn't on any family photos. That will make for great conversations when she is older.
Only agree to have a first dance reluctantly, and believe your DH when he says he has specifically hired a band that will play the song you have both chosen and the bridesmaids when they say they will join in after 1 minute. None of this will happen, you will end up shuffling round awkwardly to the theme from cheers while the bridesmaids shout at your ex boyfriend to get up and dance with your mother.
Agonise over your choice of reading, as your DH loves poetry and is pouring over his books to find the right one. He will announce that he isn't doing a reading AS YOU WAIT IN THE WINGS and so you will have to just rant on a bit in response to his short and sweet statement of love.
...and breathe...
It actually was a lovely, relaxed day, that was a bit of a shambles (I welcomed the first few guests in my jeans) but the only bits that didn't really work were the formal bits that I didn't really want anyway, so it's ok :)