Well, obviously, there isn’t necessarily a “right” answer to this question. The eternal advice with the tarot is: do what feels right. Most people choose to simply shuffle overhand, but due to my extensive experience (read: I’m a huge giant gamer nerd) with nerdy card games, I know that this isn’t an adequate method of randomization. That is to say, the cards remain in a trackable, predictable order when one only uses the overhand shuffle. Which is why I violently riffle all of my cards. I want the cards to truly be in the order that they fall in naturally, and this is the method that I think achieves that. Sometimes I’ll throw in a few overhand shuffles if the cards tell me that there is a pocket of cards somewhere that needs to be elsewhere. Other than that, riffle riffle riffle.