I always take a little case with me that contains things like a Tide stick, safety pins, klenex, double sided tape, eye drops, a sewing kit, black socks (6 pair), lotion, tic tacs and a few odds and ends. It has come in more handy than anything...
I'd add q-tips, hand sanitizer, tylenol/advil and bandaids to this kit. But agreed, these sort of things are always forgotten the day off a wedding and you're a god/goddess in the eyes of your clients when you can save the day.
I also keep a cooler of at least 2 litres of Gatorade and 2 litres of water in my car (helps keep me hydrated and lessen the exhaustion the day after) and shove a bunch of chocolate chip granola bars and fruit to go bars in my camera bag.
Well I wouldn’t say "the hard way", just experience. During the Reception....Follow the Bride, the others will follow. Keeping the frame in a horizontal gives the Bride/Groom a great look at all there invited guest. I complete the Reception phase still adding about 20% of the Reception vertical
Get your back up equipment out of the church quick smart. Once was taking some quick snaps outside the church when the priest who was in a hurry locked the church with my gear inside and left the premises!