Your search should commence with your own family and local sources. Immediate attention should be paid to those sources which are at risk, including oral information, papers in the custody of individuals, and gravestones.
These may be followed by a search of the civil registration records of births, marriages, and deaths, and the census records.
You can look up the indexes to the births, marriages and deaths and copies of the census records when you come to The National Library of Wales, either on microfilm/microfiche or through using Ancestry Library. Otherwise, you can see them at the Family Records Centre, 1 Myddelton Street, Islington, London, EC1.