How do i prevent stealing?

[TeRMiNaTe]

The best way is to be online. Than very few players will attack you. And if somebody attacks you, you just fleetsave for a minute or two (before the attack) and direct your ships back to the planet. There is another way. Making defenses... It is very boring, but no player will ever go on your planet for at least 3 months.

[Cocko]

You get a large rectangle in the overview tab, it looks just like the the ones you get for your own fleets but its red, that lets you know that hostile fleets are approaching. It tells you the remaining time, type of the mission (spy or attack) and, if you have L8 espionage, the number and type of ships that are approaching.

Yes, it's necessary to have several cargo ships for fleetsaves. You fleetsave by loading all your resources into your fleet and sending it to attack an inactive player (i) or to transport or station on another of your colonies.

[Seyhall]

As others have said, fleetsave. Yes, you need cargo or, better, megacargo ships to fleetsave. Search for that word in the forum or look at this explanation by Harkon: http://www.bulfleet.org/forum/index.php ... t&p=362330

Also, you have to be active. Even if you fleetsave, if you are away from the game for 12 hours, somebody is likely to steal your production.

And don't overlook talking to people. Talk to your attackers in a positive way. Use humor. If they become friendly, the chances that they will steal from you become less.