This is a very nice cake, I think you've done a wonderful job.
I posted a picture not too long ago of the first wedding cake I ever made. I've since made many more cakes, though not wedding cakes.
Here are a few good tips...
When you ice your cakes there are a few ways to make them smooth. The first one is to use a 'crusting buttercream' recipe. After your icing crusts a bit you are supposed to take damp 'Viva' brand papertowls, place them on the cake and smooth the frosting with a fondant smoother.
The second is my favorite method. It's the one my mom uses for wedding cakes. Put on a crumb coat of icing, ice over that, and the place your tiers in the freezer. Leave them in just long enough to freeze the icing. Then take a new clean sponge, dip in hot hot water and squeeze out the water. Then wipe your frozen icing smooth. Dipping in water often enough to keep the sponge hot.
The hot sponge melts the icing just enough to make it very very smooth. This gives it that look that pro cakes, and cakes covered in fondant have. Then you can refreeze your iced cakes for a few more minutes to make sure your icing stays smooth.
Make sure if you are going to use colored buttercream with this method that you only use gel colors. Regular liquid food dye will bleed out of the frosting. I learned this the hard way, as evidenced by my first ever wedding cake.
This time is year, most craft stores have sugar flowers for cakes, Wal-Mart does as well. They are premade edible flowers, fairly cheap, nice looking. These cover up all sorts of things.
Fresh flowers are also your friend.
To pipe small things use sandwich bags that don't seal and just snip off once small corner. So much cheaper than buying huge amounts of icing bags if you don't have need for them again. You can also do this with a coupler and tips. If your bags split and break, your icing is too thick.
And my favorite, they sell these almost everywhere where you can buy cake supplies or order online. It runs about 10-12 bucks depending on the store.http://www.amazon.com/Wilton-Floral-Garland-Cutter-Ejector/dp/B0000VMBL0
I think I use mine to death. You roll out fondant, gumpaste, candy, etc. And then use the cutter like a cookie cutter, then press the flower into the cakeand push the plunger like a syringe. So very very very easy. Then you can pipe a dot of frosting in the middle. makes very nice tiny flowers that look like they came out of a bakery.
Hope your cake comes out lovely