What a broad topic. Research, for a writer, encompasses so many different things. For example, today I watched a show on Ian Fleming and his role in WWII and how it related to his James Bond series. Fascinating stuff.
Then I watched an episode of The Rockford Files. We've got the entire series on dvd. The mob had surfaced again - it's kind of a staple - and while they were being true to form, there was one spot where they discussed the difference between NY pizza and the stuff offered on the west coast.
So. What do these two shows have in common? Well, for the book in progress that involves Carla, Gino, and the Mob, plenty. For the second book in the WWII series involving Katrin and John, plenty.
The point is that everything is research for a writer. People we meet. Places we go. Appliances that break down. Strange stuff that pops up in the course of the average day. It's all grist for the mill. It's all research.