I always carry a Large Pillar and some Ceilings on my Argy. If I see any big dinos worth taming I place the pillar and the ceilings on it, land on it and just tranq safely from there. Just make sure your flyer doesn't go flying in front of the dino. Also, as usual, get ready to run after the dino before the last shot. So probably better to clear out the area first if you can.
If you want to knock it out effortlessly, place a wooden cage and lead it towards the cage. It will start attacking the cage. You can shoot it with tranq arrow and BOOM! You have made it unconscious. Also, it eats berries.
These are really easy to tame for later players how have the saddle. First you have to make a trap. The items you’ll need are 16 doorframes, 4 foundation’s and 4 ramps. All stone except the ramps of course. Then you will have to make it mad and lead it into the trap. After you’ve done that tranq it with arrows. Once it’s knocked out fill it with mejoberries or the preferred kibble. Preferably use soothing balm if your using mejoberries. TADA 🎉 you have a thery enjoy your new super awesome mount. 👍