I have found that a fantastic way of tracing many of my family members has been through using military records. We are very fortunate here in Australia to have relatively straightforward access to the records of those that have served in the Defence Forces.
Some of my favourite places to begin searching include:
Australian War Memorial – http://www.awm.gov.au/research/family.asp. Users can search an extensive database of nominal rolls, rolls of honour and commemorative rolls. There is also access to photographs, private papers and diaries.
World War II Nominal Roll – http://www.ww2roll.gov.au/. Includes the details of approximately 1 million men and women who served in Australia’s Defence Forces and Merchant Navy during WWII.
The AIF Project – http://www.aif.adfa.edu.au:8080/index.html. Created by ADFA, this web page includes a searchable database of approximately 330,000 men and women who served overseas in the First Australian Imperial Force from 1914 – 1918.