To get the formula, you criss cross the charges. To name it, you say the name of the metal, then the name of the nonmetal with an -ide ending. If it is a metal from DForP block, then you use a roman numeral to indicate the charge of the metal. Basically everyone gets a Roman numeral except S-block, Boron, and Aluminum
After learning the basics, students practice.
Ionic Bonds for Dummies
Here is a cool interactive where you can build models to simulate ionic bonding.