Ok you sat and you had a great conversation with yourself, the side that wants to know everything and the side that is more practical and it is advising you it is best to slow and focus, because if not you will miss important information. I hope the latter won this argument and if not then I highly encourage you to go back and revisit (hint, hint, wink, wink).
So now that you have decided what to focus on, now you want to take a notebook, open a word doc...whatever is your preference and start writing everything down that you know about that person or person. Let's pretend you have chosen your paternal great grandmother, mother of you grandfather. You will write her name and start writing everything down that you know about her. You could follow these prompts:
Date and Place of Birth:
Date and Place of Marriage (s):
Date and Place of Death:
Name of Spouse (s):
Name of Children:
Additional Details: (Here you want to include any stories you have heard of her. Even include why do you want to know about her. In this section even what you think may not be significant can be used as a clue)
Congratulations you have completed the first step to begin you research and the first piece of documentation for you Family History.