The best way to tame one is to get a creature that can tank a lot of hits and make sure you have at least for hemoglobin for a max level and then I personally use my bronto that has 40 K health and a platform saddle, the higher, the armor rating the better but I just let the Cerato attack me and then I can dismount and help defend it from the platform saddle and I’ve consistently been able to tame 150s without worry of my bronto dying just make sure you pay attention to how long each hemoglobin has left so you can use another one if needed