The Ice Caverns map is set in an arctic tundra, with frozen platforms, hills, and tunnels all around the map. It is one of the biggest maps in terms of size, but the appearance is very repetetive along the entire map.
When playing as the Engineer, place killstreak turrets on top of the middle platforms. That way they will have a clear shot in 4 directions.
When playing Capture the Flag, the AI tends not to tread on the bottom ground platform. Take that into consideration when you are running with the flag.