Aside from the obvious (no cash bars, don't kick out bridesmaids, etc), what is some personal advice you'd give someone who's just started planning their wedding?
Obviously I'm not married yet, but in this planning journey, here are my best pieces of advice:
1. If you're the type of person (like me) who says "yeah, that looks good, let's do it" and then regrets it a week later, don't pay your vendors all at once. We didn't do that with any of ours, but we almost did. We lost (thankfully fairly small) deposits on 2 vendors and have paid too much to find a new photographer, even though we're unhappy with their work. I guess the moral of this story is: do more research. But if you don't, don't pay your vendors off immediately.
2. You know how they tell you not to look at other dresses once you've bought yours? I'll amend that to say "If you're sentimental and have already firmly decided not to book a videographer, don't watch wedding videos."
(One more in comments...)
