You start with who you have! In order to raise egg production, or at least keep it as high as possible, you need to know who your best laying hens are to start. or, do the flock mating system, and hope that by saving eggs for a week or more to hatch, at least odds are that better producers will have more eggs in the basket.
Roosters are no better than their genetics, and selecting cockerels from your best producing hens is what you need to do, and that again means being able to ID offspring individually.
Don't neglect other important selection criteria, like structure, good health (especially for more than one year!) and temperament.
Have fun with your project!
Mary