The smallest clue can lead you on a voyage of discovery back in time.
Alternatively you can look more closely at those you have already found; it might be worth concentrating on the end of a life, and see if your deceased ancestor left a will which often contains information about property, possessions, occupation, family and circle of friends. Indeed, occupations can be followed up in a number of ways; you can investigate a military ancestor's period of service at The National Archives, whilst professions such as coal mining or cotton factory workers can be investigated in local archives. The smallest clue can lead you on a voyage of discovery back in time.