How do I produce a better offspring?

[Adryel]

I've been researching ethical breeding, looking at known breeders, the dangers of combining certain genes with one another.

As for a breeder who is looking to start, how do I ensure that I will produce a better offspring from their parents? Such as their health, tameness, and a good size.

I've had past experience of breeding, but, for the last few months, I realized the real purpose of breeding, where one should not just go, and do it without extensive knowledge, and would like to know on producing better offspring.