Coach Peter Russo has some good, smart hockey stuff. Stick length comes up all the time. A lot of support for his approach.
The short version: Lower your flex and cut your stick. Stick length should be around the collarbone while standing on skates.
He’s got pictures of many of the greats–Gretzky, Lemieux, Crosby, Ovechkin, etc.–demonstrating their stick lengths. Read all about it at http://coachprusso.com/2015/05/06/hockey-stick-length-explained-why-i-carry-a-hacksaw-to-lessons/