The easiest way I've found to boost this is to play Survival. Pick your favorite tank (I use the 2nd tank under the US, I don't know if this is DLC or not, but whichever you like best), and start a match on the 3rd map. You get 1000/kill, -200/death, and points for time spent playing. I usually get at least 5 kills, so it's around 5000/game.
Each level takes more points than the last. I'm at level 5 right now, and it takes 25,000 to get to level 6. This will be a bit grindy. If you like the game, it'll come naturally. If not... well, this is the easiest way since you're not competing for kills with other tanks.
Hope this helps!