Even though this was posted in over a month ago, I have this game and am new to the forums. So why not give what I have learned and hopefully gain some recognition at the same time?
Risk 2210 A.D is very similar to Risk, however the differences are important and unless you learn to master the differences you will be stuck playing Risk, while everyone else uses the new and different rules to blow you out of the water.
The best and possibly biggest of these differences is the destroyed territories. (For those who do not know, in Risk 2210 A.D 4 random land territories are "devastated" these territores cannot be used at all. However they do not stop you from getting the continent bonus if you have everything but the devastated territories.) The coolest thing about this is it makes sure that everygame is different and forces you to come up with new ways to attack and defend your empire.
In my experience it is estremely benneficial to group yourself around these territories. Even if it makes it almost impossible for you to attack another player, it is still important to surround yourself with these territories. It causes other players to just not want to deal with you. You can survive and while you may seem like a small unimportant player in the early game, you can become a force to be reconed with in the late game.
The next gigantic difference is the addition of the moon. DO NOT UNDERESTIMATE THE MOON. The moon is 14 territores and the big moon "continent" is worth more than Africa. Even if you are walled in on the land and on the water, you can still expand by conquering the moon. If you can dominate the moon, you become very powerful, very quickly. This is important as towards the end of the game, you can hope invade the earth from the moon and suddenly strike the heart of your opponents empires. Yes you need an invade the earth card, but you will be able to get one if you really want one.
If you are able to wall yourself in with devastated lands, and control the moon, you will find yourself to be a strong player who is very difficult to attack. By the end of the game (which is turn 5 in Risk 2210 A.D) you should be the strongest player or one of the strongest players, and give yourself a pat on the back.
That is what has worked for me in the past, become a strong difficult to attack empire and you will be impossible to destroy by the end of the game.