To survive day 15 in Tribes of Midgard, you will need to prepare starting from day one.
On day one, your first priority will be to repair all three worksites. Doing so will allow you to build up resources around every 10 minutes from shipments you will receive from these worksites.
The quarry will net you cut stone and wrought iron, and the lumberyard will net your wooden boards, all of which are required to build and upgrade the gates and towers of your village.
You will also have to build and upgrade all gates and archer towers to their max levels if you want to survive to 15.
Building these gates and archer towers will make managing horde nights a lot easier to do and keep hethings in place, making it easier to get group kills.
But to upgrade both gates in towers in Tribes of Midgard, you will also need souls, the currency that fuels everything in the game.
To get souls, you will need to clear camps, which can be located via camp icons on your mini-map or world map. Clearing the entirety of these areas of enemies will reward you with some souls, but the real profit to be had, is with treasure chests.
Treasure chests give the most souls, and if you want a lot of them, you will need to farm these chests that can be found in varying sizes in camps in the game.
We also highly recommend getting a ton of souls, at least 5k for each person in your group, so you have enough to repair your weapons/armor and rebuild structures in the village.
Gather enough souls, and you will be able to fully upgrade everything in your village, which brings us to the next step.
Getting better gear and raising your power level to around 300 is another crucial step in preparing for the long winter ahead of you. You can get both better gear and a higher power level by crafting more advanced gear in the game.
We also highly recommend focusing on armor that provides the most protection from cold and in general. The reason why is that when day 14 comes, the world will be in endless winter, and so if you want to leave the village, you will need extreme cold protection.
For weapons, we recommend ones that have lighting damage, as the foes you will face are helthings, and their weakness is lighting. You can also make better gear at both the armorer and blacksmith, but you will need to upgrade them to gain access to better items.
That said, once you have achieved all of these steps, you will be ready for the big horde night that will arrive on day 14. When the night arrives, you will need to manage all three gates, which will be easier if you have a few friends with you.
Also, before day 14 comes around, make sure to kill the Jotun. If it is not killed already, split your group into two teams, one holds the village, while the other kills the Jotun.
Doing so is vital as you can not hold both the village and keep the Jotun out at the same time. Plus on day 14, the Jotun will have a crapload of HP that scales with the number of players.
So the best thing to do is kill it before the big night comes around, as you will not have enough time to kill it if it comes too close to the village.
To conclude, once you reach day 14, you will need to hold the gates and constantly repair them, assign players to each gate and keep killing helthings. Eventually, day 15 will arrive, and you will get a brief hiatus, and the helthing spawns will decrease.
When this happens, send a few players out to quickly get supplies/souls if needed, and then repeat the same steps and hold the village. Doing all of this will get you to day 15+ and beyond.
Check out some more Tribes of Midgard guides at Pro Game Guides!