Let's say you own a planet with multiple wormholes to enemy planets. What kind of defense do you build to destroy the enemy waves?
My typical setup is to place the command center behind one of the wormholes so that it is out of the way of the space trains. Put a forcefield over the command center, poweplants, and factories, and place exo-ffs on the resources. Turrets are positioned outside the ff, between the command center and the enemy wormholes. Maybe put some tractor turrets in front of the damage turrets, to grab the enemy bombers before they can shoot my ff. Add about 20 mk1 cruisers because I hate AI bombers, and move them under the ff when threatened by anything other than bombers. Also some mk1 ships to counter the expected enemy types. Mines on the approach routes if the attack will be tough. The AI ships generally head straight for the command center (because the resource harvesters are hardened), and they spread out as the faster ships get there first. So the turrets don't have to fight the whole wave at once, and I can move my counter ships in or out as needed.
Actually, I don't build much defense ahead of time. Just keep about 100,000 crystal in reserve, and a spacedock and an engineer or two at each planet. When I get the wave warning, I pause and then start building the defenses I need, deleting them at other locations if I'm at the population cap. Build times are very important here. Most mk1 or mk2 turrets build in less than three minutes, but stronger versions need to be in place before the wave warning. Two engineers are enough to build a mk3 ff in three minutes. Some ships build much faster than others, fighters are 2 seconds each, bombers and cruisers are about 10.
How are you guys doing it?