User research doesn't have to be loads of time, but you do have to know how to do it well. It is focused on understanding the problems users are facing. Something as simple as 15 minute calls with users/potential users can help you to gather data.
Usability testing 101 by the Neilson Norman Group
by NCVO and Neontribe
by Jeff Haden
by Joe Roberson
by Nikki Anderson