I am going to attempt an Elsa and Anna from Disney's Frozen cake for my daughter's birthday.  I've never done a doll cake before.  Any tips and suggestions?

Have a look at Zoe's fancy cakes on youtube (in fact I think there is a tutorial on here somewhere) Zoe is a member here. She has some amazing Elsa/Anna cakes, including a super easy sugarpaste Elsa figure. Good luck (if you use the search bar at the top it takes you to where you want to go)

Have a look at tutorials of making cakes. Good luck and don't forget to upload a picture of your cake.

Check it out.....

and this, no pinata here