The first thing to know about Snow Wars 2 is that it is a two-level game - by that, I mean you can usually earn 1000 neopoints in the first two levels. If you want a high score, it's not all that different from the first two levels.
Scoring is relatively simple: You get one point for every square of earth you have protected (denoted by blue snow instead of white snow), plus 10 points for every snowman you have surrounded during the build-a-wall segments. Scoring is assessed at the end of the build-a-wall period, and at the end of the place-your-catapults period. You also get 20 points for each lupe you hit, but no points for the enemy catapults.
Also, terminal snow blocks are removed between the build-a-wall and place-your-catapults periods, and between the place-your-catapults and shoot-the-lupes period. By this I mean that any blocks of snow that do not touch other snow blocks on at least two sides will be removed - and if they're within the surrounded space (blue snow), then you get one point for each block removed.
The game starts with you, a few snowmen, and a trench over which you'll be firing shots. Start building a wall around your snowmen. I usually start on the right and work my way up, then over to the left across the top, down, and back towards the bottom right-hand corner of my square-ish wall system:
Once it's filled in and the timer for the build-a-wall part runs out, you'll get the option to place catapults. In the first level (and the first level only), you can put down n+1 catapults, where n is the number of snowmen you've surrounded. In this example, I can place five catapults (four snowmen plus one). You can see here that I'm starting to do just that:
Notice that the terminal blocks have been taken away? Pay special attention to the top portion of my wall, you'll see what I mean.
Once you've placed your catapults (or if time in this segment runs out, whichever comes first), you'll move into the shooting phase of the game. Fire two shots at each of your opponents' catapults first, then take out the lupes. With lupes, I fire one shot where they are right now, and one shot immediately in front of them. That way, if they move towards my walls, I can still hit them.
One thing about the lupes: you can't build snow walls over top of them. And they move during the nonshooting phases of the game. But if one works its way into your protected area, once you complete the wall, it will disappear. If one begins munching on one of your snowmen, that snowman will quickly melt. And a melted snowman is worthless to you - so if you have a lupe inside your protected area, build it up quickly!
The opponents' catapults will shoot at your walls. After the shooting is done, you can repair them. You should...you know...do that.
And you'll get blue snow again when you've filled in your walls.
Once that's done, again, you'll have some time left over. Remember what I said about terminal blocks? If I set the red-outlined piece in this picture down, I'll get three points afterwards - because it has three parts that only touch one other block.
Also, starting in level 2, you can only place as many catapults as you have snowmen.
Notice the score in the upper lefthand corner. As I write this, the game payout for Snow Wars 2 is two to one - so I've already hit 1000 neopoints. After just one and a half levels, I might add.
If you want to set a high score, it's basically the same - lather, rinse, repeat. There are two points worth knowing, though:
1) As you progress, more enemies will appear.
2) Once you hit about 25 catapults placed, you've got enough. Any more is just overkill. There is no possible way to fire more than about 20-25 shots before your first catapult reloads. So just sit back during the place-your-catapult phase and relax once you hit that number.
Good luck!