1. Always "source" your genealogy information.
2. Be consistent in how you store people's names, dates and place names.
3. Use software to help you.
4. If you are blocked going backwards (you have information on a person, but can not learn about their parents), then research the person's siblings, and then learn about the sibling's parents. After all, the parents are all the same.
5. People who have the same name are not necessarily the same person.
6. All sources are not created equal. In general, written sources are better than remembered facts; records at the time of the event are better than those created years (or decades) later; official documents are more accurate than unofficial ones; and so on.