I set them right by their freshly filled water dish and then I start flicking my finger in the water to make it move.
Sometimes I have to scoot them so they are halfway in the bowl while I am flicking the water.
If they don't start drinking, I will put a drop of water on their nose. If they don't lick that off, I will take my fingernail and lightly scratch their lips to trigger a licking response. Then while they are licking, I will put another drop of water on their noses for them to lick off. And then I'll start flicking the water in the bowl again.
Those few steps are almost always enough to get them to start the tongue flick required for drinking. Their bodies will flatten out into a pancake shape and they will duck their heads. Sometimes I'll gently push their heads into the water if they are trying to drink too high above the bowl.
Once they are flattened and drinking, they can drink for up to 8 minutes. Their bodies will stay flat and their eyes will half closed. It's adorable!
It took me over 18 months to train Ziggy how to drink. I kept repeating the process over and over again both with his water dish and in the bath. He finally learned and drinks immediately when he sees me filling up with water dish.
Usually once you get their tongue flicking triggered, their instinct takes over and they'll drink. The key is moving water. Instinct tells them stagnant water is bad. That's why most beardies will drink in the bath-- because they are moving the water around them.
Oh and it's very common to see them gasping for air for a couple minutes after they've been drinking. And the next few poops will be very runny.
And usually my beardies drink good once a week. In the wild, they store up water when they find it. It's okay if you don't see them drinking every day.
Here's Drake who was a little confused and was trying to drink in the corner of his tank. Silly boy!
Next time I "teach" a beardie to drink, I'll try to get a video of it.