Hiya Taylah's mummy
I dabble in cake decorating myself here are some tips.
First up you obviously need to hire a tin.
Make sure you make a realtively dense cake like chocolate or madiera otherwise you'll end up with a crumbly mess.
Remember to level out your cake. I have a specific cake leveller but you can just eyeball it with a serrated knife.
With regards to the icing:
Most of the cake is covered using a fondant icing. My favourite brand is pettince which you can buy at the supermarket for about 5 bucks. Before you use fondant you need to put a thin layer of butter cream icing underneath the cake to 'glue' the fondant to the cake.
Rolling out and colouring fondant
Before you roll out your fondant, it is really important that you give is a good knead with a little bit of icing sugar mixed with cornflour to stop it from sticking. I use a bit of bit of vegetable shortening to get it moving. It's at this stage you may want to add some colouring to the fondant. You need to use paste rather than liquid food colouring as you'll bugger up the the texture.
When you roll out the fondant make, try and have a plastic sheet (some kitchen shops sell sheets with markings for cake sizes) which is dead flat (you could iron it) with some shortening to stop the fondant sticking. You want rolled out to about 1/4 inch as if it is to thin, the fondant will stretch.
Making figurines:
Add some gumpaste to your fondant to 'stiffen' it up a bit.
Other stuff:
Make sure you keep your fondant well covered when you are working with it. There's resuable gladwrap you can buy from the stores which is more expensive but fun to work with.
An easy way to 'cheat' with fondant is to roll it out and then attack it with cookie cutters.
Both of those cakes have cake boards underneath. You can either buy them at specialist shops or make them (just a bit of really stiff cardboard and some tin foil stuck on).
Here's a cake I made recently (just because I love to show off)