How to tame:

Step 1: Build a trap near but not too close to your desired spino.

Step 2: Lead it into the trap. (Don't underestimate their speed!)

Step 3: Shoot it with tranq arrows/darts until it goes unconscious.

Step 4: Put your taming food into it's inventory, and wait.

Step 5: Enjoy your new spino! (These guys are really good :D)