Enter the battle mini-game with the first power-up received. Do not wasting time waiting for it to get all the way to the end. You can then a few of them before each battle. However, when you need new warriors go for them, especially when the recruit bars are next to each other.
Loot cave
Build storage space in your loot cave to hold resources that are safe from other players.
Movement
When at sea, you will have to deal with incoming shots and predators. You can shoot at them to destroy them, while rowing forward as fast as possible to reach your destination. Note: After an area is discovered, you can tap its name to travel there an no longer have to row across. The rowing mini game earns experience for your Vikings, based on the distance traveled. Consider occasionally starting at the first mission and rowing all the way to the last available mission to earn lots of experience. Make sure to refill your shots when they are low and use the auto fire if desired.
Resources
Scroll to the left until the menu appears, then select the "Free Loot!" sign to watch video advertisements in order to receive random resources. Resources are randomly awarded each time a land or a water attack is completed. After destroying a barrier, enter and collect the loot. Note: Nails can only be obtained in land battles. If you are short on troops, more can be hired in town. Tap the "Weapons & Heroes" icon, then tap the middle icon on the right side of the screen to recruit extra warriors for 50 gold each.
Troops
Before starting a land battle, tap the "Manage" button and upgrade your troops. There are four categories that can be improved, however you will be limited by your resources. Consider upgrading the most powerful areas first, such as extra troops. Focus slightly more on an upgraded land battle. The boat only seems to be important when destroying the barrier, which can be taken down in several attempts at an energy cost that regenerates for free.
Upgrades
Each time you collect extra weapons of the same type, they can be upgraded. Tap on them in the "Weapons & Heroes" menu and spend coins to increase the chance of success. Consider using the maximum setting in to avoid losing your weapon if there is a failed forge attempt.
Land battles...