How do I balance redox equations in acidic reactions, without trial and error, using half equations?

Here is a summary on the steps to complete these question types. 

1. Determin oxidation numbers 2. Figure out what is being oxidised and what is being reduced. 3. Write half equations. 4. Balance the atoms exclusing O and H. 5. To balance O add H2O, to balance H add H+. 6. Add E- to balance charges. 7. Multiply half equations so the number of electrons on each side =0. 8. Combine the half equations by adding together and cancelling out molecules that appear on both sides. 9. Final check to ensure all is balanced correctly.