Use the "Fleet" button at the bottom to set a fleet for defense. If other players attack your base, they will be countered with the ships you have set there. When you leave the game, set some of your strongest ships to defense.
Gems
Log in for seven consecutive days to increase the daily rewards. On the second day, you will be given 50 gems. After gaining every two or three levels, you will be awarded a level plan pack. The packs contain resources, boosters, and gems. The amount of gems will increase the higher your level. Participate in special events to get gem rewards. Play the "Aims" side missions. After successful completion, you will be given a reward that often includes gems. There are three "Aims" categories: Basic, Military, And glory. Basic missions are generic, Military missions involve fighting other bases, and Glory missions are related to your own personal growth.
Medals
As the storyline progresses, you will occasionally earn medals. Medals are can be spent for officer upgrades. The officer skills add permanent bonuses to your units during combat.
Resources
There are six location that you can build on the empty field to the west of your base. Resource buildings will be placed here. Use all the available spaces at that area and keep the resource production buildings upgraded to their highest possible level. You will occasionally be given resource rewards which will be placed in your bag. When used they will immediately give you resources such as gold, oil, etc. Save those rewards for times that you are in danger of running out of resources.