Usually writing articles and posting them to article sites like ezinearticles.com is very good. Although it takes time to write articles but in the long run it's worth the effort.
You can also setup a facebook group and invite your friends, friends of friends who are students to join your group. Since you'll find many facebook users to be students I think this strategy will definitely work.
You should also participate in forums specifically geared towards students and comment/answer questions. The click through rate to your website will increase.
Read my 9 Tips to Generate Free Targeted Web Traffic.... http://www.d3webdesigns.com/free-target ... affic.html
Hope this helps.