I usually don’t watch free practice sessions as I need to be at work on Friday and FP3 is not shown live on any of the TV channels that I can watch.
If I, however, happen to be at home on Friday, then I try to watch at least one of the FP sessions on TV. I’ve also participated at F1F live blogs a couple of times and I’ve really enjoyed it although I prefer to concentrate on the race action on Sunday.
For me, the most important part of Friday is making predictions! I normally first read F1F’s FP analysis as well as Mark Hughes’ analysis on Autosport to try to understand what’s going on and then make my choices.
Both on Saturday and Sunday, I usually do something non-F1 related in the morning (go shopping, to the swimming pool etc.). Sometimes I watch the whole pre-race build up, sometimes I don’t feel like that and turn the TV on only a few minutes before the race starts.
Just like @th13teen, I also read quotes, opinions & analysis after each session but I similarly first need a break from the electronic devices after watching F1 for many consecutive hours on Sunday!