There are certain ways that you can adjust your accounts druing war time to lessen the loss.

1. One tactic is running to a different reality.

Sometimes considered cowardly but a good logical move if you do not want to participate in a war. Secondly good to wait and see if anyone from the other army runs to it and you are there to catch them.

2. Selling off your defense (weapons) and re-training defenders and sending Mothership away.

If you have supers triained leave them armed so that at least kill off some of the enemy. Sell off any extra defense weapons (so they don't get sabbed) and put it to something like raw UP or if your crazy like me pumping your MS (don't do this, unless your crazy). Sending your mothership away is easy, click the button for it to search and it is gone for 24hours. It takes it away from being massed.

3. Hiding your planets with MPSD.

This requires that you spend market turns to aquire MPSD, but 1 MPSD will hide a planet for 24 hours.

4. Attack!

For those that love combat and don't care how longs it takes to rebuild account (could be like 4 months at the least). Sell you defense pump your strike and if your MS isn't that big (at least 20 Billion power) then send it away, also if your covert isn't that big Raid instead of Attack.