Tip 1: It's often worth scrapping out the first wave with your solitary flagship in order to see what's needed and use your resources effectively.

Tip 2: Early on, you might want to go with the XP bonus perk while the going's relatively easy so you can unlock some of the better ships quicker.

Tip 3: Remember that artillery has to travel, so you might need to 'lead' your targets if you want to make a direct hit.