After you buff off the rust, rinse the blades again. After rinsing the blades, dry them with a towel.
Make sure you always keep the file at the same angle during the entire stroke. Never file toward yourself. Instead, make sure you file away from your body.
If you have bypass or anvil style pruners, you will only sharpen the beveled cutting blade. For all other types of pruning shears, repeat this step on the opposite blade.