1) Always contact the florist! The bride told me there'd be a "cascading floral topper" so I made the top tier slightly taller to accommodate it. When I delivered the cake, the florist had only left those 5 random flowers. The bride wanted me to "arrange them on the cake"! Wish I'd checked with the florist to find out exactly what she was bringing for the cake!
2) Make sure the SPS plate is centered BEFORE stacking! I had to unstack the bottom 2 tiers (thus messing up the icing & having to scrape off the crusted icing & re-ice!), re-position the SPS system, and restack!
3) Be ready for an audience at the venue. I was prepared to have the wedding planner, florist, etc. watch me finish assembling the cake (stacked top 2 tiers onto bottom 2 on-site) but wasn't prepared for the bride and her parents watching me! Pressure!
(Mod edited to provide working link.)
Wish I could see the picture but it isn't coming up. Glad everything turned out.
I thought I'd add what I learned... on my third wedding cake though.
1. Always have a plan B and maybe even a plan C, because things don't always work out as planned! (Seriously, when planning your cake, think to yourself, 'if that doesn't work, I'll do this instead...')
2. Condensation is the enemy when it comes to working with fondant! Make sure your cake is completely thawed and at room temperature before crumb coating it and covering it with fondant.
3. And as you said too, expect an audience! I didn't think I'd have the whole wedding party watching. It was raining outside so everyone got to the venue early. That wasn't fun, lol!
Maybe we can all learn from each other instead of having to learn the hard way!