I usually only folow the forums of various Indie games I like becouse almost all of them have and Off-Topic section with atleast one thread pointing to other interesting games. The best thing bout this is that usually games suggested there also fit my interests as pepole who have interest in certain game also do have similar interests in other games than I do.
The other source are game reviewing sites. But I don't mind much about their reviews but I only read short description of the game and check screenshots to see if this game might interest me.
I also use Youtube quite often to watch various gamplays as it might show you much information about the game. I stoped wathcing trailers long ago as they rarely provide much ifo about the game (great trailer for crappy game).