Play and win. Offer some advice after the match. Frankly if people are gonna quit because they can't beat you then those people are usually the first to start chucking dice at kids so good riddance.
Any issue with always being the winner? (Flyin' Casual)
I usually try to discuss the game after. I've thrown my opponent good advice, reminded them of actions and tokens. It makes the game seem more than it is when everyone is flying at their best.