Let's see. I haven't studied every turn, but here are a few tips:
Your biggest mistake is that you picked Congo, it is never a good idea to start in a territory in a wasteland.You probably won't ever attack that wasteland, so it is a wasted pick.
Second, in turn 8 you met your opponent and you never expanded after that.
It usually pays off to keep expanding slowly. You'll get bonuses to have en edge on your opponent, and you'll also collect cards!
So after you met the opponent, it would've been better if you'd spent 3-5 armies per turn to get West China and then East China + Central Russia.