Best way is to wait till the hairs on the buds turn colour and start to receed back into the bud...then the bud will be at it's peak potency and also be at peak flavour. I hear everyone saying to use the trich method, but in actual fact you shouldn't go by it at all...i've had plants that had trichs 50/50 by week 4, but the hairs were all mostly still white...you wouldn't wanna harvest then. Don't forget there are also 52 more ingredients that make up cannibus, 3 are the main THC, CBD, and CBN, the THC isn't everything, you must have your CBD and CBN at there peaks as well.