Amongst the most relevant information required at this stage are details relating to family members, names (even of those stillborn or who died at birth or shortly afterwards and whose existence might have been temporarily 'forgotten'), dates of birth, marriage details  and dates, details and dates of death, and various other family events including baptisms, educational and career-related information, and so on.

Next is the task of interviewing family, friends and relatives; the older the better, as long of course as time has not weakened the memory.
Old family legends are often the motivating factor in making that decision to trace and document the family tree. Stories of blue-blooded ancestors, famous relatives, criminals and heroes, all are handed down from generation to generation. Many of these tales will doubtless have been expanded upon and elaborated with time, but it is always worth recording even the seemingly tallest and unlikely of stories; it is not unknown for a germ of truth or even a totally accurate legend to be still making the rounds of the family. Write it all down, or if your interviewees don't object, take a small recorder with you to tape the conversation ready for transcribing to paper when time permits.
Amongst the best sources of information virtually guaranteed to set you straight on course for access to the family history in recent decades, hopefully up to a century or more, are family bibles, photographs (often with messages written alongside or on the reverse), diaries, letters, and tombstones. Access to any of these items, even if you must sit and physically take notes from whatever source is available, will prove a more than worthwhile investment in terms of the time, trouble, and sometimes expense involved.

Photographs

Old photos can be on of the best resources for researching your family tree. Many times the date and place that the photo was taken will be on the back of the photo as well as notes from a family member, The type of clothes that your ancestor was wearing can give you a clue to when it was taken if there is no date. The buildings in the background of a picture may also provide you with a clue as to where the photo was taken. 

Postcards

Postcards can also be a good source of information. Many times an ancestor who moved away from the family home sent postcards to keep in touch with their family. Postal marks and photos on the postcards can provide important clues about where to look for ancestors.

Family Bibles

Family bibles are probably the best of the resources you will find in searching out a family tree. Many families kept records of births and deaths as well as smaller family trees in the family bible. Look through the whole bible because sometimes you will find notes written in the margin that can provide clues.

Your Search Begins-Where To Look And
What To Look For

Once all family sources have been exhausted, now comes the real challenge of investigating from official-sources, and not just central records offices and county registers. There are many, many other repositories of information available to the researcher, all of which must be considered in relation to the actual family and whether you  wish to restrict your investigations to a limited period of history, or instead, uncover anything you are to able about your family as far back as time, money, and ability allow.

The most logical and easiest next step is that of obtaining all official documents relating to recent generations as it is possible to obtain, a task usually accomplished from birth, marriage and death certificates held at your county courthouse. All information is of course committed to the basic tree format already waiting on paper or computer disk. Any other information to come to light and which might be clarified or expanded upon from other official sources should be noted for working on when the time is right, and includes such as relatives known to have a military record, those known to travel who will therefore have had their passport applications from 1795 onwards registered and so on.

Once you have a dear indication of your most recent generations, you will be able to track down copies of birth, marriage and death certificates from civil records which go back to the mid 1830s. Since mandatory registration it is relatively easy to trace a tree back to the second half of the nineteenth century. Then the really hard work begins.

Census returns are an excellent source of information relating to household members, and provide information gained every ten years  since returns commenced in.

For much information prior to civil registration, we must turn to  county records, which can usually and quite easily take the investigator back to the mid 1700s, perhaps earlier where families have remained in one area. Records can be consulted at your county records offices, or sometimes from the International Genealogical' Index, or Percival Boyd Index, the latter of which covers the period 1538 to 1837.

Local newspapers might provide obituary details; gravestones also are havens for previously evasive information.

Wills might uncover a skeleton or two for the unsuspecting detective.