You will get this achievement eventually when you will be going for several other achievements but for some reason you haven't or you want it earlier then there is a easy way or you are finding it difficult to play a specific game mode type. For me i completed the game first and later on downloaded the DLC's so i had to boost it some how.
For all connoisseur achievements you need to play every game type on every dlc map. This is completely random and repetitive. You can check which game modes & maps combination you need through statistics>Levels menu.
1. First of all to minimize the chances of randomness keep only one dlc in your xbox Hard Drive at any given time. Either delete other dlc or move them to flash drive (remember to remove the flash drive from console). Must be done by all players in the session.
2. Minimum number of players required = 2 ,but can be more.
3. Choose any server mostly West Japan. All players search in "Variety Pack - DLC maps"
4. There are 6 game mode types although 'Marked for death' doesn't count but it will still be there and 3 maps. Total of 18 Unique combinations. These combinations may repeat several time.
5. You only need 2 players to start the match though it may take little longer to start than usual time as game keeps looking for more players.
6. When you get a map and game mode required by all players then play whole match as usual. If not then one player (considering there is only one player in that team) should quit and after couple of seconds the other team will win as there will be no player to fight against and match ends in no time.
NOTE: If you quit the match before it has started then you will end up in the same map/game mode even if you change the Server location/Data center.
7. If there are more than 2 players and all of them needs to play the map and game mode except just one say that player be 1. Then everybody from player 1's team quit and join someone on the opposite team to players 1 through xbox guide button. When everyone is in opposite team and player 1 is alone then he can quit and let other players win/end the match.
Extra Tips:
Don't Quit Last titan Standing matches as the might not register as win for the other team.
On quitting too many matches like 10-15 by the same person then game may not let you leave. Happened only once with me.
This achievement can be combined with 'Victor' achievements for all maps as well as with the following achievements.
Hope This helps...