Things You'll Need
Instructions
Log in to Xbox Live, choose "Play Halo: Reach," and wait for the game menu to appear.
Go into campaign mode, and change the mission to ONI: Sword Base. Turn on the "cowbell" skull, and set the difficulty to heroic. Enable team scoring in the campaign menu.
Select "Start the selected mission," and wait for the mission to load. Once it loads, start running straight through the mission without worrying about the enemies. Try not to die, and run downhill toward the large structure.
Go into the structure, and find the target locator. Turn around, aim it at the group of enemies outside of the structure, and hold the trigger down to call in the strike.
Squat down behind something to take cover. A checkpoint should save right before the strike comes in. Press the "Start" button on the controller, and select "Revert to last checkpoint."
Watch as the enemies are blown away by the artillery rounds. Once you've collected some medals, revert to the last checkpoint again and earn some more. Keep repeating the procedure for as long as you'd like to maximize your credits.