Bring lots of narcotics! On the center they are mostly in the redwoods. Sometimes they spawn in your base (if you live in redwoods) use a bola and have a couple because it takes awhile to get their torpor up(it drops quickly) use kibble so you don't have to use as many narcotics. If you want to use berries or crops, you should wait until double xp because it goes up slowly and uses more narcotics the longer the tame. Make sure to tame quite a lot, too. Their eggs are valuable. (Depends on the server how valuable)

More Gallimimus Taming & KO Tips