A good place to start is the Japan Blog List. Here you can find blogs written both by Japanese people and foreigners, so you can explore different perspectives. The blogs also specialise in different aspects of culture - for example, Hiro's blog concentrates on food whereas Purple Pen, who comes from the Phillippines, is interested in the Japanese school system as she is a teacher by profession. So you will find plenty here to interest you.
You should also try the Blogs Directory - this is full of ideas, and in particular Muza-chan's Gate to Japan (the first on the page) is fascinating and very well organised. It has sections on customs, food, history, little known facts and other aspects of Japanese life, besides including a photo a day.
This is possibly the most detailed and all-round interesting blog, but you should certainly explore the others on the page - several go into detail about specific aspects of Japanese culture, such as anime.