If you are stuck for what to write about, ameba blogging service have an excellent feature called blog net kuchikomi (I think this means something like chit chat/common topics)
Ameba (アメーバ)｜ブログを中心とした登録無料サイト
Basically it is a set of questions about anything from your favourite type of ice cream to what you think of underage drinking problems.
I am at a low level but find the odd question I understand enough to answer.
Pick a question you understand click on it to put it as the title of your post, write an answer, your answer gets rated and you get pretty items for a little avatar thing. You can also click to read who else answered the question and read their blogs.
If you have any questions about using ameba feel free to pm me, I found it quite confusing at first.