Establishing family relationships is a critical part of building a family tree. The further back in time one goes, the more difficult this becomes. Before 1790 there are very few census records and most do not list family members. However, there is one type of record that is common back to the earliest known records in Europe and the US.
Church Records
Church records can offer a wealth of genealogical material about your ancestors. Most denominations kept some type of record of their members. Some included baptism, marriage and death information as well. Some records in Europe go back to the early 1500s. It is important to determine what records exist and where they can be found.