Take some time to browse through Comiket's official English page: http://www.comiket.co.jp/index_e.html
Make sure to pay special attention to the rules and guidelines laid out in the address to attendees from overseas, here:
http://www.comiket.co.jp/info-a/TAFO/C81TAFO/C81eng.html
Following these rules will help make the event run smoothly for everyone!
