I always felt a bit disappointed in TNG for not revealing more about the backstory of each of the characters, most notably Data. Worf and Riker were the most developed, with us meeting family and knowing about previous Starfleet vessels, etc. Even with Picard we don't know much exect slight glipse at childhood (Family), Academy indescresions, and time on Stargazer. We know nothing about Picard between the destruction of the Stargazer and him getting the Enterprise-D.
The book, The Buried Age, by Christopher L. Bennett, went a long way toward a detailed timeline for Picard during those years, including how he meet Data, who was still a LT. and just a glorrified records keeper after over 15 yrs in Startfleet.
It's always been my belief that Data had a pretty mundane career in Starfleet for years, possibly right up until just before Encounter at Farpoint, when he met someone in Starfleet (possibly Picard) that saw that he was capable of much more than just simple science and records keeping and gave him a chance at command.j