What's the easiest way to get Overkill, Killing Frenzy, Save This Film and Have Fun

[Eric]

Respawning in Halo 3? Overkill: Get an overkill in any ranked free for all match
Killing Frenzy: Get a killing frenzy in any ranked free for allmatch
Save This Film: On a Mythic map get a perfection medal in any ranked or social match
Have Fun Respawning: On a Mythic map get an extermination medal, with at least an overkill, in any ranked or social match
Any tips on how to get these achievements?

 

[Sarcodine]

just keep on playing really, you got to wait until you get lucky and the opportunity comes to you.