Always keep your workers busy with building, upgrading, or cleaning up your base. In addition, it’s possible to clean up secondary islands even before you buy them.
Don’t let your hatchery sit empty; keep it working on eggs. When you upgrade to hatching two eggs at the same time, keep one side available for quick-hatching eggs.
There are limits on the number of attack points (for multiplayer) and the amount of stamina (for dungeons and islands) you can store. Once you hit that maximum number, get out there and fight.