Knowledge

The most useful early techs are those that enable better tools, and sledges. Prioritize these.

-Make sure you look at the milestones for each of the main campaign levels. They provide a huge amount of knowledge and are not too difficult to achieve.

-Before advancing to the 4th age, where Reindeer, Cave Lion, Cave Bear, Woolly Rhino, Mammoth and Ancient Bison will go extinct, hunt these animals to at least the times 10 level (Rhinos are usually solitary though, and hard to get). Getting these early knowledge points makes tech advancements much easier

-Knowledge is the ultimate finite resource. Trade for techs as much as possible, even if you have to starve or freeze your humans. ‘Saving’ knowledge points particularly in the early game makes late game research much easier.

-Usually any building times 5 gives a knowledge point. You can build and then demolish structures to reach this. Also spam spirituality totems to at least the times 5 level.