You will need a large table and lots of terrain. The rules suggest covering a third of the table with terrain. I find that half is better and two thirds not too much. You need the large table to give room for manoeuvre.
You should put a few layers of terrain between starting positions and objectives, so that there is not too much open ground to cross. If you don’t do this, then the player starting with the initiative has it too easy advancing to objectives, while retaking objectives will be too hard, since it will be so easy to place defending troops in the right place to ward off an attack. You need lots of small pieces of terrain. Actually, I’d say that the amount of the table covered by terrain is less important than the number of terrain pieces, because big bits of terrain (you should have a few, though) are little more useful than small. The number of pieces of terrain between one place and another makes more difference than the amount of the table covered between one place and another. With lots of bits of terrain, defenders can not sweep large areas of open terrain with their fire, are more easily frustrated by smoke, and can less easily predict the direction of the attack.
