This can be done via a rented server with one other person. Servers cost 120 MSP for one day.
You must have the server set to ranked. Unranked and private give no awards, xp, or achievements.
Set the server to start at 2 players minimum, 8 players maximum. Also set the tickets to 20% of normal. This keeps people from joining from quick match, and also allows you to end the round quicker when you're done.
I found that it was rare to have someone join the rented server while we were working on these, but if they do, you can hit start to pull up the server settings menu and remove them from the server without leaving the game. As an admin, you can also swap players from teams at will.
I found Gulf of Oman Conquest pretty easy for this. Get into a party with the other person. As a US assault, with an assault rife, use the US F35, and fly to the road leading from the RU base to C. Brake hard and it converts to hover mode. Set it down, and kill the RU player. When the RU player respawns at the RU base, have them drive a tank up for you to use to kill them again. Hop out of that and use your assault rifle to gun them down a final time. Switch sides, and repeat for them if needed.
The rented server method works for pretty much any of the multiplayer achievements like
The Third Tour achievement in Battlefield 3 worth 41 pointsGet a kill with each of the following vehicles: the BTR-90, DPV and F-35.
or ribbon boosting.
Keep in mind that DICE has been known to reset people boosting this game. I would not use this method to boost ranks, as it gives you an unnatural score per minute, which seems to be what they reset for.