Stupid Viking Tricks:
1. When you're chopping wood, especially in a place you've cultivated for growing trees, give each tree a whack or 2 with your ax, starting in the middle of your grove. When one tree finally falls, you can step back and let the falling trees do the rest of the work for you in a timber cataclysm. You can also chop 2 or 3 things at once (if they're close to one another) to save time and wear on your ax.
2. Your boat will turn faster if you go to paddle mode. Not such a big deal with the karve since they're so maneuverable, but in the longship it makes a difference when you're tacking.
3. Torches definitely when you get the event "The forest is moving." It keeps the horde to a manageable size around you.