Unreal Tournament III

You earn a hat trick for capturing three flags in a row for your team in a CTF or VCTF match. If you are playing through the campaign on Casual you should earn this just from playing those missions, as they do count toward this trophy. Just make sure that you are the one always capping flags. If one of your teammates has it you can tell them to drop it by pressing and then choosing the drop flag/orb option.

If you end up needing to clean up this trophy after the campaign you can easily play it by setting up an Instant Action game with no bots. On a small map such as Suspense simply capture the enemy flag three times in a row to win the match. Repeat until you earn the trophy.