• Birth, Marriage and Death certificates
• Baptismal certificates
• Wills and testaments
• News clippings, or copies of magazines.   Journals and other magazines that relatives may have written for, or been written about. This includes amateur publications such as church or society newsletters, based on what your relatives were involved in.Don't throw out anything until you have checked through it all!
  
• Photographs. These have an article all of their own
• Military service records and medals: You need to identify what regiment your ancestor was in, and prefereably his army number too. That gives you access to many records.
• School, university, and other educational certificates and awards. Learn about your ancestor's educational attainments.
  
• Business and other occupational documents, and trade union record. What was he up to in his work?
• Diaries. Hope that these are not written in indecipherable code, such as my mother-in-law used. It was her own private version of Pitman shorthand, unreadable. But we picked out a few names and dates!
• Letters and postcards - kept by anyone in the family tree.Odd documents sometimes include useful data.
  
• Tape recordings; film or video recording. Did anyone make a record of the family's activities?
• Books and other items with inscriptions or dedications: check the fly-leaf!
  

There are many more possible sources, depending on the family background. Use your imagination, and ask your relatives for help.