Get a pocket microscope to check the trichomes! That's the only way to know if they are ready or not. If all trichomes are clear, your plant still contains too many precursors to get you a satisfying high. If all trichomes are cloudy, you could harvest immediately if you want to, but most growers wait until they see around 10-30% amber trichomes because that's when the buds will hit you the best!