I always trap half of all my planets (So Beware!

). Planets that have been scanned or attacked, i usually Brick, Lots of Defence and i buff then 24/7 with Ion Repulsors (Would usually have around 16,000 Def + Good Production). No Attack (Minefields).
I Rarely Cloak, only have Cloak on 1 Planet (Only 3000 Cloak). It only has special Structures that have cloaking bonus's, No Standard cloaking satelites on it.
As for Invasions. I only invade that planets when i have close to 90% Chance invasion. Before Wiping out population, i drop Ion Storm and Mass Disruptors. Max Cannons and Activate all Attack Buff Artifacts. Spam Click Attack. Then Invade.
If i happen to lose a GOOD planet. I will just sell/give it away if it's too heavily defended. If it's lightly defended, i will wait one week before attempting invasion. (Like this terra i just lost, the idiot Gaiaed it and only placed a few Null Minefields... Waiting for traps to expire, will be my 7th Gaia

)