Starting out on your family history work backwards from the known (yourself) to the unknown (forebears). Fitting all the pieces together so that they fall into place, you need to work methodically and don't jump generations. Start by gathering together documentation of your own family, birth, death and marriage certificates, notices from newspapers, cemetery inscriptions, photos etc.
NEVER believe everything on a Birth, Death or Marriage certificate.
NEVER completely trust the spelling of surnames, places names etc. as transcriptions from original documents can be difficult to read and result in incorrect information being copied.
ALWAYS check surname variants when researching.
ALWAYS have at least two separate sources of proof for each event.
REMEMBER that everything is only speculation until vertified.
ALWAYS photocopy certificates and important documents and leave the originals in a safe place.
NEVER carry original documents around with you.
Information is not all on-line, there are lots of tantalising leads on the net, but you also need the assistance of visiting a Family History Group, Genealogical Society or Historical Society to look at original documents. Obtain a blank pedigree chart. Free downloadable and printable charts are available from Family Search and Ancestry Library Edition websites.
SHARE your information and documentation (copies only) with other researchers.
The National Library of Australia database TROVE - Treasures of the National Library is useful for searching family and local history. A search for Sam Merrifield as Keyword, selecting Australian content turned up 207 results in Australian newspapers (1803-1954), Books, journals, magazines, articles 10 results, Diaries, letters, archives 3 results and Archived websites (1996 - now) 60 sites.