Chops is a cool trick. Once you master it, you'll find that audiences love it. It's one of the few tricks that's as difficult as it looks, but once you get it, you'll feel very rewarded!
I'm assuming you know the basic pattern. There are a couple suggestions I can make. One, do doubles on the throws, it slows things down a lot! Secondly, I would break the pattern down to two clubs. Learn how to toss that double, then chop with the other hand. Always work both hands equally.
Dick Franco's "Three Club Juggling" will help greatly. Heck, he's doing the trick on the cover of the book!
Hope that helps.
Troy Roark