SO this is the cake i made for mine and Justin's engagement party. as you can see, its a pretty amateur attempt. HOWEVER, i have to say, for only watching 1 season of cake boss and being a first time fondant user i'd say i did pretty well! The sides of the cake are sloppy [even though i worked hard to smooth them] but the cake was a total hit with my fiance's family :) [it was yummy too!]
also keep in mind that i work full-time, so this cake was *started* at 11pm and then decorated the next day *before work* at 6 am. Next time, when the circumstances are better, the cakes will look better; i'm sure of it!
The most important part of making a fondant cake is making sure the cake itself is level. Take a knife to the sides to make sure they are even all the way around, then do your crumb coating of icing. Then put on a generous amount of buttercream, or your choice of icing. That gives you a a nice margin for error.
If you have a dent or groove somewhere, it makes it easy to smooth over.