Pay Attention to Witnesses and Informants

Often, on the records, the people listed as "witnesses" to a wedding or "informants" of the information (births, deaths) are close family members. Pay attention to these people. Search them out. Knowing more about them will help you to know more about your ancestors.
For example, my great grandmother's wedding registration lists her sister, Janet, as a witness. This particular sister was one of three sisters that my great grandmother had. But she was the oldest sister and the eldest child. My great grandmother was next in line. These two would have taken on a great deal of household management together as their sibling population grew. This helped them to forge a strong bond. The bond in fact was so strong that when my grandmother had her 8th child and was living next to her mother in law, my great granny suggested that the child be named after Janet's husband as a way to honour his role and position in the family. Thus, my uncle was named William Lorimer Colquhon Crawford.
It was also learned that when my grandfather's first wife, Sarah, died in childbirth, the baby that survived was raised by my great granny's sister, Janet. My great granny took over care of the eldest 5 children, but the baby was placed in the care of her favourite sister. The two women lived close to one another and so the sibling group was essentially kept intact. Naming my uncle after this sister's husband was also a way of saying "thank you" for this couple stepping up and caring for my grandfather's baby after his first wife had died suddenly. Janet was in no way obligated to care for Sarah's child. She would have been assisting with her own grandchildren. But as a favour to my great grandmother she opened up her heart and her home and took the baby in.
So, pay attention to the seemingly minor parties on certificates, so some sleuthing and you will be pleasantly surprised at the bonds and connections you find. This will help you to flesh out more intimate details about your ancestors and will add to your living history of them.