A simple cake can be beautiful and elegant.  One way to quickly decorate a cake is to use fresh flowers.
Here is a list of safe flowers.  Remember that while some flowers are edible, it is best to just use them as decorations.  Make sure they are pesticide free before using.
Apple Blossom, Malus spp.
Begonia, (most tuberous), [...]

Your cake needs a place to rest.  Most of the time your simple round cakes will do fine on a cake plate or cake pedestal.  However, your other sheet cakes will need a cake board.
Some options for cake boards:

hardwood pastry boards
plywood
foam core
cardboard
masonite

Once you’ve chosen a cake board, you’ll need to cover it.  You are probably [...]