I guess you don't. Lets see....
Last year, I was touting Jerome Robinson from Boston College, who rose from the 30s in mocks to the lottery on draft night. I wanted Troy Brown from Oregon for the Jazz who rose from the mid-20s to #15. I liked Rodions Kurucs in the 2nd round, even the year before that, and he's panned out.
A couple years ago, I called out Bam Adebayo when he was mocked in the late 30s, then he went in the lottery to Miami.
This year, I started touting Kabengele when most mocks had him in the mid-30s. Now he's moved up almost 20 spots. Bazley just jumped 30 spots, though maybe some of that was easy to predict.
If I'm wrong about Grant Williams and he becomes a significant player, you can call me out on it. ESPN just moved him down from 23 to 32 in their latest mock. I don't like him as a 4, and he's not remotely a 5. If he were longer or super athletic in a Clarence Weatherspoon sort of way, I could get with it, but right now he's meh for me.