I was having trouble beating the game until I read another person's tips.  Then it was a piece of cake (bahahaha...).  Then I started over and it took exactly 4 hours to beat it.  Anyways...I thought I'd add some more tips:

- Whenever you have enough money to buy a faster oven or frosting machine, buy that first.  Then move to buy decorations.  A few months in the first level, you'll definitely need new shoes.
- This might be obvious, but it wasn't for me for a while.  When bringing a cake to be frosted/decorated, you can just click the color/decoration.  You don't have to put the cake down and then click again for what you want.
- You need the TV by August on the beach.
- You need cupcakes by Feb at the circus.
- The men (with short hair) are very patient and usually want very simple cakes (towards the end they will ask for a decoration).
- The old ladies want double cakes towards the second level, and then switch to wanting single or double with that silly purple man decoration.
-The teenage boys are extremely impatient starting during the beach level.
- Once you get the strawberry decoration, all the teenage girls will ask for it on their cake.
- All the cakes in the December level on the beach are Christmas Trees so you can make them in advance.
- The teenage boys love that silly blue toy with the weird eyes.

And the trick to winning is:
- Don't pick up all the money.  Keep 1 or 2 on the table at all times once it starts getting busy.

Enjoy!