After you've exhausted your home sources within your own abode, it's time to visit or contact your parents, grandparents or older relatives- to interview them and ask questions about your family. Hopefully you'll run across your family historian--every family hopefully has one. When preparing for your visits, gather a list of questions you'd like answered and some means of recording that information- either writing down what they say or asking their permission to record their voice on a tape recorder or video. Sometimes older relatives are more comfortable with you just taking notes, but you'll loose their exact words which you might want to quote in sharing this history with others.
At the beginning of the visit, take time to just converse and catch up with what is happening with their lives before you launch into 20 questions. Show genuine interest and love for them and their opinions. Tell them of your desire to write or at least gather some history and background of your family to share with the young'uns. Find some topic that interests them to start with...maybe their favorite hobby or time in their life. For men, military service experiences can get them going. One question will lead to another.
Ask open ended questions like...How did you feel about that? What happened next or how did that change your life? Don't try to ask all your questions in one setting. It can also be done through emails or letters or phone conversations that can be taped with their permission if you live a long ways away. The main thing is keep it fun and not tiring. Visiting and talking is a skill most of us could develop. Taking time from our busy schedules to visit and listen shows others we care, and that their life's experiences are important to us.