Start up a 1v1 private match and invite your friend. Set the Time Limit to 10 min (even though that won't factor in your boosting). Set the score limit to 500 points and the Respawn time to 0. Go to the "Resort" map.
First you want to get your knife kill and that will get you 100 points. Next, whip out your pistol and score a headshot which will add 200 points. Finally, use your sniper rifle and get a headshot with that to end the match.
Trophy will pop after the match ends!