Invest in a good scope that does 60x-100x magnification to look at the trichomes,though the trichomes are not the end all be all.
Things to look for for peak maturity:
1) Check trichomes with a 60x-100x scope.They should be as close to 100% milky to 90% milky/10% amber.Clear trichomes are immature,milky/cloudy trichomes are mature trichomes,amber trichomes is a signal that the thc in the trichomes is degrading converting the THC to CBN which gives a couch lock kind of high,but not a true couchlock like from a powerfull Indica.
2) Calyxes start to swell
3) Hairs not only turn from white to orange,then shrivel back up into their respective calyxes and turn a dark orange/red.
Mantra:
Pick No Kind Before It's Time!