Maximize every possible angle of the grow and hope for a great pheno!
Consistency comes down to how stable the strain is and how many/what types of phenotypes there are... I don't want to speak for everyone, there are some superstars here, but some of the large harvests you see out there are just a rare pheno of a regular sized strain, every now and then one will pop up huge compared to the rest. Seen it with Lowryder and Lowryder 2 in my crops; nothing to write home about in my case at the time but some were respectably different/larger than the rest of the girlies...(25-30+ in the woods with no attention)