A possibility is there to combine two favoured female plants in the hope of creating a unique stain of the cannabis seed which generates 100% female plants. Ideally, you want to be combining individual strains that come from different classes of plant, which aren't likely to come from a related cannabis seed.
By using the unique stains you are certain to generate the optimal offspring since the chances of inbreeding are diminished. In most situations it is easier to gauge the overall quality of the female plants when compared to the male equivalent. A reason for this is that the smoke is easier to judge and more potent in it fine qualities. Growing cannabis seeds in this way results in a complete harvest of female plants since the male chromosomes will be to completely lacking in the growth process.
Using something like Gibberellic Acid on the branches of the female plants is likely to help with inducing male flowering. Any decent garden centre is likely to supply Gibberellic Acid which is required for hybridizing and plant breeding. A plant can be sprayed on a daily basis over a ten day period with approx 100-ppm of the solution.
Once the male flowers start to appear, you might want to pollinate some of the other flowers on the selected female plant. You can just pollinate just the one unless you are hoping to generate a significant amount of seeds.
After achieving the male flowers, you want to snip the branch and relocate to pot of water. A container can be placed underneath to help with catching the male pollen. Gather the fallen pollen into a bag and give a good shake. Also use a bladed object to help with scrapping up the loose fallen pollen in the local area to include in the bag.
You might find the possibility is there to pollinate the chosen plant with the male flowers by aiming to cross it with itself. A process of this nature is certain to help with preserving any unique characteristics of the plant. A cloning process also helps in preserving the characteristics, but won't offer the option of storing the seeds for later use. A downside of this process is that inbreeding is likely to cause issues so it might not be the ideal option in most situations.
Gibberellic acid isn't guaranteed to be 100% successful in the process of generating male flowers, so you might need to conduct your own tests to establish if you are able to succeed in this process.