Start with what you know about your family. Record key dates for the people you know (birth, marriages and death) making sure you are clear about which dates you have evidence for and which are guesses. Focus on full names, dates of birth, marriage and death, and where these events occurred – geography will be important as you search for family members who may not be familiar to you.
Talk to your relatives but remember, memories can be ‘selective’ or at variance with the facts.
There is also (unverified) advice from an organisation called ‘Home Advcice Guide’ here