Best way is with a paracer and cannon on top. Find a mountain cliff side and place 2 high pillars in a semi circle, 8 pillars should do. Leave one side open. Agro the Elemental with a bird preferably so he doesn't throw rocks. Once he walks into the trap, sprint away from his targeting range. This will cause him to De-agro and go back into a disguise. Keep your distance when returning to it. Go to the side that you left open, with pillars in hand, and sprint in to place the 2 tall pillars as fast as possible. (Dino Gates work as well) I would recommend have a sleeping bag or bed nearby. Now comes the tricky part, find a rock or structure to hide behind that is near him, get his attention and wait for him to just stop moving and stare at you. (You need to be on foot) If he does this, back away and he will stay like that. If not, Get close to get his attention and repeat. Now simply aim and fire. 20 balls for a 120. You must hit it in the head and it must do a dramatic flinch.
It's a bit silly that kibble tames it a lot better than rocks or sulfur because even in the dossier it says that it lives off of absorbing nearby rocks and minerals. So mabey they should make it so you have to feed them a rare mineral like obsidian what if they made it so you could tame one fast and with high effectiveness by giving one a few hundred or few thousand obsidian . or what if there kibble was made out of a combination of ores and minerals .