You might think oh this is going to be hard to get no one is playing the game, but since it's been announced that they are removing the game from the EA servers next month, there are more players than ever coming back to Battlefield 2 on the Xbox.
Now if you Quick Match in to a game, you might just end up joining this on going game were there seems to be some Bot players that just stand at the Non American Base and you can just gun, C4, Grenades, etc. them down for your achievements or what ever you need.
Just remember to join the American side and head over to the enemy spawning base, or join the opposing side and have fun trying to getting out of being spawn camped.
I still need to try to get a few more Online Achievements but I got all of the other ones:
Air Force Cross: Online - I'm not that great with flying and aiming the air ships.
Expert Use of Mortar: Online - I think I might get this one.
Mechanic: Online - need to find a full game were I can repair a lot
Medic: Online - not sure if I will ever get this one.
Navy Cross: Online - the map with the boat is called Honor and its near flag 5.
Later when the servers are gone, or if MS decides to host them, we will just have Campaign Single Player, too bad they don't have the game set up for system link.
Good Luck and Good Game!