Yes, as the Imperials, be sure to have a marksman or two to protect yourself from the turrets. Without this cover fire, your men will likely be cut down by fire from above, which doesn't help that much.
As the Rebels, try to make the best use of cover. Your nice green clothes help you to blend in, especially when prone. Another bonus is that, even when lying down, it's easy to spot a massive clump of white in a green forest. Just hide in a bush and blast 'em.