Assign oxidation states using standard rules
Free elements have oxidation state 0
Monatomic ions have oxidation state equal to their charge
Group 1 metals are usually +1
Group 2 metals are usually +2
Fluorine is always -1
Oxygen is usually -2
Hydrogen is usually +1 with nonmetals and -1 with metals
Sum of oxidation states in a neutral compound is 0
Sum of oxidation states in a polyatomic ion equals the ion charge
Solve for the unknown oxidation state algebraically
Check the result against known oxidation state rules