A few multi/triple kills with any gun
Pick a song and make the video as long as the song IF you sick like IReapZz then you can pull off like a 10 min video but make it like 3-5 mins 5 being the max.
Music: Dubstep.. Rap.. Maybe something a bit heavier.
(make sure you sync your clips to your music)
what guns do you like to see? - Any weapons really as long as is isn't something like the AA-12
what kind of editing? SYNCED music editing. You have to sync music.
how long should it be? A good montage is normally around 5 minutes.
what kind of music? Music with a lot of variations and beats.
what kind of clips? Multi-kills, trick shots, equipment, lucky kills, FMJ