It's Moo's 2nd birthday very soon and this time I am determined to make his cake myself

Any tips for a novice like me? It's got a little bit of cutting involved and lots of icing/decorating. Is it better to freeze ahead? When would I actually ice it, on the day or night before? Is it better to use a cake mix or make from scratch?

I'll be doing a practice one some time in the next week so appreciate any hints!