Finding People further back than the late 1700s (General)

by rookancestrybest , United Kingdom, Saturday, March 20, 2010, 22:03 (5444 days ago)

I know for definite that Thomas Rook (born 1784 and died 15/3/1844 in Lane End, Coleford) and his wife Elizabeth Mary Stead (born Jan 20th 1786 Bristol, died May 26 1866, Lane End, Coleford) are my direct ancestors.
I have also traced Elizabeth's parents and grandparents.
However, I can find a Thomas Rook born October 10th 1760 (in Littledean) who died in March 1809 (in Newnham) but I cannot find conclusive proof that he might be my Thomas' father nor how many siblings the Thomas born 1784 had for definite. What can I do to check this information and to attempt to go back further?