I have a customer that wants a Princess and the Frog cake with Princess Tiana on top made from fondant or modeling chocolate.
I have never sculpted anything so any help would be GREATLY appreciated
For a tiara you could cut it flat and then dry it in the traditional curved shape that wouls probably be easiest. You cann draw or find a tiara image, sioze it properly on your computer & print it, cut it out& use iot as a template to cut out the tiara from gumpaste. After it is cut (I use an exacto knife) you can drape it over a 2 liter bottle or other properly size round item to dry.
How far into the future is the cake you will be making? When I 1st started modeling with fondant I purchased some Polymer clay books and they were a great help in getting me started. They give you the basics on what you need to know. You just have to adapt slightly for using fondant.
I just went and checked through all of my clay books to see if I could find a frog, but believe it or not, every animal but frogs! A frog is fairly simple to make. I know this website seems to be running a little slow, but take a look at some of the pictures in the gallery, there are tons of ideas for inspiration. When modeling with fondant everything starts as a ball and you go from there. I'd be glad to answer any questions for you if I can.
I use Satin Ice fondant with tylose powder added for my figures. Ratio: 1 tsp Tylose to 1lb of fondant.
Here is a link to Lorraine Mckay's blog. She is an amazing artist and has online tutorials you can purchase that might be of some help to you.
Good luck with your project. Have fun with it.