Hi there, welcome to Splitcoast.
3D can be great fun. My biggest tip would be to measure and cut as accurately as you possibly can - mismatched pieces will never line up and give you a smooth, professional finish.
The prettiest shoes I've seen are
these - she has a link to the template (it's from Craft Stamper magazine).
Mirkwood Designs has loads of free templates including 3D stuff.
Waltzingmouse Stamps has some cute templates (check under the Digital Products link for templates) - some free, some to buy.
If you encounter particular issues you can always start a thread here and somebody will most likely be able to help.
Hope that helps to get you started!