The connection is the biggest opponent. We faced some consistent lag throughout. Things will be fine then they will get a little laggy. Other than that, have the best player be the designated person to plasma pistol the shields/armor off the brutes. Make sure to know what weapons to use and when... and lastly, have a gameplan for all the hammer guys.
It's tough, but not impossible. I had my most issues with the game dropping people out. Had to do this about 7 times until we got it.
Please check out my Halo channel: http://www.youtube.com/MixMaker117
100% COMPLETED HALO PROFILE!
Marathon: Durandal / 100% (15/15 Achievements)
Halo Wars / 100% (58/58 Achievements)
Halo 2: Vista / 100% (41/41 Achievements)
Halo 3: ODST / 100% (47/47 Achievements)
Halo 3 / 100% (79/79 Achievements)
Halo Reach / 100% (69/69 Achievements)
Halo: CE:A / 100% (44/44 Achievements)
Halo 4 / 100% (76/76 Achievements)
Halo: Spartan Assault / 0% (20/20)