I believe match bonus is mode dependant.
If You play S&

the longer U stay alive + kills amount + what kind of kills eg kill bomb planter/defuser, so sometimes its not worth to rush get 3 kills and die in 10 seconds.
On Team Deathmatch its mostly kills based and avenger kills (helping team mates), getting assists (easy just throw flash/stuns all the time at the enemies then let team mates kill them)
On Domination don't rush across the map, cap as many flags as you can, BUT when you hear WE LOSING ... A/B/C quickly go back kill them - PROTECT your flags. Once i had aound 15 kills but 3200 score due to capturing and defending flags constantly (i'm not asking you to camp at flags

)
More team work/playing objectives rather than being a kill whore = MORE POINTS.