Hit and Run
by Thorax

A great strategy I have found is to use single shot missile ships.

Basically build a ship with really poor system speed (for the extra room) and fit the largest missiles with all the trimmings (i.e. shields, armour etc) and set it so it fires multiple missles but only one volley.

The idea being to build flotillas (4 core IF ships, no escort/picket required) of these ships. Put 10 or so in a fleet and attack a system.

In the actual combat screen, select all of your ships and attack the planet. Then General Retreat to safety, since your ships are now completely defenceless, and watch the desctruction. Since the missiles are from lots of different flotillas, rather than from one armada, they will seek other targets (system defence ships, orbitals etc) if the planet's defences are completely wiped out.

I have used this system particulary well against the Orions. Sending fleet after fleet at the system will decimate any defences, even if they are significantly superior.

The only complication is if the planet has no defences (i.e. you destroyed them last turn) and you have to wait for some other defences to show themselves. You may take casualties in this instance. But on the plus side, these ships are usually very cheap to build since you really don't need armour or shields either.