The Beltot map seems to be inspired from the "Prisoners of War" map from the singleplayer game. The sky is twilight red, and the building styles are identical. It's basically a town, split into two sides by a road running through the middle. There's one large house on each side, a barn, passages under bridges, an MG-42 nest atop a high tower accessible by a ladder, and other unique interests, but the map is not very popular because of its quickly-stale gameplay and the tedious need to cross the road over to the other side in most TDM and all CtF games.
The MG tower is always a good place to help your team (or yourself, in deathmatch), but many times you'll find the spot useless when everyone starts taking routes that your gun can't reach. When going from one side of town to the other, it's a lot safer to take the east route with the tank; however, constantly be on the lookout for riflemen and snipers who have their sights on you from the other end of the road. Houses on both sides have roofs that you can lie down and snipe from; however, the northern house's roof is more visible to enemies.
For the Americans, there should always be a sniper or two in the house in front of the flag, since this is a prime position to stop enemy steal attempts; even if it does get taken, if you're quick enough (and guess the direction right) you can stop the carrier. It also helps to have someone lie prone in the small shed-like area right behind the flag, as it's very hard for the enemy to see (but be ready to hear the word "cheap" from the other team). Sometimes, if the Germans have an aggressive team, your house may be taken over. If this happens, submachine gunners should rush the house from both the main entrance and the basement while others stay back and grenade/pick off enemies in window areas. Support gunners should suppress the enemy riflemen so they can't attack your teammates while they try to rush the house.
As for getting the enemy flag, your team should occupy at least one of the two houses on either side of the barn (and hopefully the barn itself) to make it easier for the carrier to make the getaway. Throw smoke and move in, and if you're not going for the flag yourself try to occupy the barn. As in all Capture the Flag matches, one or two other player(s) should back up the carrier, more importantly so in this map because of the threat of snipers on the roads.
For the Germans, the important thing is to not let the Americans take the houses on your side of town. Also, the second level on the barn is a nice place to watch your flag. Which direction you assault the enemy flag is not very important, since the Americans have plenty of windows to shoot from on both sides of their house. Be careful of enemies hiding in the shadows behind the flag or spawning in the house as you try to get away.