A guide on how to easily earn some XP early game by killing prehistoric turtles.
Find a Carbonemys. They are common around the beach areas found throughout Ark.
Craft a few spears. The engram is unlocked at level 2, and each spear costs 2 flint, 8 wood, and 12 fiber to make. Flint is gathered by hitting rocks with a pickaxe. Wood is gathered by hitting trees with an axe. And finally, fiber is gathered by hand from bushes. Once you have all the materials and have unlocked the engram, simply press V and craft some.
Now for the most important part: killing a Carbonemys. To do this, hit it with your spear to aggro it. Then, keep hitting it with your spear(s) while at the same time keeping your distance(aka periodically backing up while hitting it). After several hits, you should have your result: a dead Carbonemys.
Step 4 (Optional)
Now that you've successfully killed a Carbonemys, you should see a spike in your XP, or even a level up; especially if you did this right at level 2. And now that it's dead, you can harvest it with a pickaxe, axe, or even your bare hands(not recommended). You will get meat, hide, and maybe some keratin from it - all of which are useful resources.