Good job for your first cake. I used to do wedding cakes years ago. I spent many a night icing cakes to the wee hours of the morning. A few I'll never forget. It was a warm & super humid night. The humidity was so heavy it was like pea-soup fog. We had no air conditioning. I had a 4 tier wedding cake to do for the next day. My violet roses kept sliding off the cakes. It took me all night & part of the next morning to get it done. Another cake I did was so tall (over 5 feet) & had so many pillars/brandy sniffer, etc, I couldn't assemble it. I left a note for them to assemble just before cutting, as the table they had was too wobbly. My fav was a strawberry themed wedding cake. I made 47 strawberries in all sizes for that cake.
Many are now using paper towels(Viva is the choice brand) gently pressed to smooth icing, but it also leaves a sort of imprint/design. When I took cake classes back in the late 70's I was taught to use hot water to get perfectly smooth icing.
There are great forums on the Wilton site.
http://www.wilton.com/cakes/making-c...-inch-pans.cfm The link is in the left column. Tons of recipes/photos/ideas/etc. This one lady has a super recipe for buttercream icing. It's to die for. Go to the site & look for "Bunnywoman's buttercream" in the recipe forum.
Happy decorating :).