The 8th edition of Monash Debating Review has recently been made available at http://www.monashdebaters.com/mdr-order.php. Editions 4-7 are also available on the same site.
This is the only peer reviewed journal on debating and is an excellent read for someone looking to delve further into the theory and strategies of debating.
This year's featured article is "There is no spoon: Beginner, intermediate and advanced first principles debating" by Tim Sonnreich. This is an excellent guide to using first principles to become a better debater on topics where you do not have a detailed background knowledge which is quite a common situation at Worlds.