The basic building blocks of a family tree relate to birth, marriage and death, and these events are covered by civil registration after 1st July 1837. Before that date the most accessible records are the Church of England parish registers which record baptism, marriage, and burial. You may find "In Memorium" cards for the weel-to-do. Church and graveyard memorials usually record the date of death, and often age and relationship information. Wills (when proved) also give the date of death and relationship details - but most people in earlier centuries did not leave wills. If the death was sudden there may have been an Inquest.
Even when it was legally required to do so, not all events would have been recorded, and even if they were errors will have crept in, as A Comedy of Errors has clearly shown. As one goes back in time the number and usefulness of records decreases, and less and less have survived, and there comes a point on everyone's tree where it is impossible to follow the ancestral line further using these tools. In particular the earliest parish registers date from 1538 and there are other key starting dates as - for example many earlier parish registers were lost at the time of the Commonwealth and in this case the registers start from 1660.
A more recent difficulty relates to the fact that non-conformist records were not covered by the same legal requirements as were the Church of England records. The 1837 date is crucial here, as there may be no surviving birth or baptism records for your non-conformist ancestors.
One of the most used indexes of family event information (particularly before 1837) is available online free at familysearch.
During 2012 FindMyPast are to digitise the Hertfordshire Parish Registers and Bishops Transcripts held at HALS up to 1910 for baptisms, 1928 for marriages and 1990 for burials.
In asking any questions you will need to provide information about family events and the sources of your information are important - so please read Sources and Reliability.
Other Useful Links
The Society of Friends (Quakers) kept their own registers from the mid 17th century and should be considered a special case. See My Ancestors were Quakers. Some non-conformist births were registered at Dr William's Library.
See Spelling Personal and Place Names for information on the reasons for the variations on spelling that often occur.
See The Inheritance of Christian Names - which can give clues to whether people are related.
See The Origin of Surnames
See Adoptions - which gives some information and outlines this web site's policy in such cases.
See Family Reconstruction for advice in piecing together incomplete records.
See also Where to look before 1837 when the Parish Registers don't help - which is also useful if you want to flesh out details of your ancestors.
If you can add to the information given above tell me.
Page updated September 2008