Recently I was asked to suggest graduate students for a focused conference on a particular issue in philosophy. I decided to poke around the web pages of some departments known for work on that topic. This turned out to be largely useless. Many students had web pages - not all did, which brings up prior advice - but almost none had any specifics. Now I know that one doesn't always know specifically what one's specialization will be while in grad school. But still, if you know enough to say that you are working on, say, metaphysics, you know this because you have written papers at least for courses. So you can mention topics. My advice is that you do so - mention every topic that you know enough about that you would like to be invited to a small focused conference on that topic. Where you will meet folks working in the area, get noticed, share work, all that good stuff. Talk with your faculty about what would be good things to include, but do so. I doubt that my search was all that unusual a phenomenon, but you have little to lose by including some areas.