One way is to use ganache on the bottom (I turn it upside down and pour it on for a smooth finish) the other is fondant (I found using a fondant pleated effect worked really well) As for the top I use Wilton 1M or similar to create buttercream rose swirls then decorate with fondant accents. Example of both of these are on my fb page. Happy caking :)
Hope, Australia... http://www.facebook.com/nicecakesandsweettreats
