Both guides above are very good and useful but seeing how it is still very tough to get I thought I would share how I got it. Easy difficulty with all skulls except blind and cowbell. At the start you need to destroy the two turrets near the start point to prevent the elites from getting on them. After you do that head towards the drop shield, along the way blow up all the exploding barrels to prevent a needless death from happening. As for where you will be setting up and getting the kills, I used the area directly beneath the turrets as I was only shot at by the wraiths when I jumped up or got to far away from the area. Before the elite generals show up your goal is to kill every grunt you can to prevent them from turning into suicide ones and blowing up directly on top of you while you are in the middle of getting kills. Once you run out of ammo pick up a plasma pistol as I tried using the sword and other weapons but couldn’t get hits fast enough. The spot also limits the amount of elites rushing you to about maybe six at a time which will take longer but it is a lot safer. Took me over a hour but did it first try doing it this method. Keep trying and you will get it.