What is the simplest way to ice and decorate a cake that makes it look as
good as bought in a shop ?

I have made the cake from scratch, and its turned out quiet good.
Now I need to ice it.
So do you have a fail proof way of icing the cake and making it look good ?
Or do you know of something else that I can use as icing to mould onto or
around a cake ?
What are some do's and don't with icing and decorating cakes ?

TIA
Nic