What do I need to know?--First time making a layered and tiered cake

[kjlutz]

So I want to make a 2 tiered cake and I want each tier to consist of 2 layers (because cake tastes better that way).

What do I need to know so I don't royally screw it up?  When should I bake the cakes (they are for a Saturday Dinner)?  When should I decorate them?  Do I need dowels to support the second tier?  What else should I be asking that I don't even know about?

I should add that I do have lots of experience baking cakes, just never with decorating or assembling them with any success (typically things I make taste great but look like a 4 year old did the decorating (no offense intended to 4 year olds )).

Thanks so much.