Contact submitters for information. Do not ask for "everything they have on the family," but instead offer to share your research in exchange for the information you are missing. Ask particularly about sources and their research practices. If the researcher is someone who is happy accepting a typed family history his or her Aunt Agnes wrote fifty years ago, treat the information as you would any other data and verify it before you accept it. Create a separate database containing unverified information. As you verify and source the data, you can move it over to your working database; by keeping the unverified data separate, you keep your working data accurate. By now you've probably realized that I've been beating the "verify everything!" dead horse. Verifying data before you accept it as valid is a very important part of genealogical research. Many researchers go beyond the norm and won't accept a piece of data until it has been verified by numerous sources, but for the most part you should examine each fact, locate the origin for that fact, verify that the origin is legitimate, and document the source thoroughly. For instance, if I found a birthdate on a World Family Tree CD for an ancestor, I would first contact the contributor to find out where they found the information. Armed with that info, I would track down the source (birth certificate, town records, census records, etc.). If that source was valid, I would then rest easy about accepting the fact, and make a detailed source for it in my database program. If the source was not primary (for instance, a birth date given in an obituary), I would note the source and continue my search for a primary source, such as a birth certificate.