What's up Josh, glad to have you as apart of the Monster G Line board..Although your question could be answered in multiple ways I like to study the dogs and there peds. Knowing what genes and traits your breeding helps out when looking for Dams and or Sires in order to achieve the look, size, bone, and head ect..There is always trial and error. Learning from the mistakes you may have made once to ensure they aren't made again! Anyhow I hope some of this may help you out along your way.