The best thing you can do for these tests is, as I'm sure countless people have said before, doing as much fitness training as you can, especially running. It is a test of your VO2 Max - how much oxygen you can take up and get into your muscles. The best way to improve this is by being as fit as you can. I know it sounds obvious, but people are talking about doing stuff like running on a machine and upping the level, but this does not take account of turning 8-12 times a minute nor does it simulate real running - get out on the road and get some experience of drag and make sure you push yourself - half of the fitness test is psychological and pushing yourself to your absolute maximum, which should hurt a lot.
But either way, it is ultimately a test of how well you can run between 2 small markers - so practice turning quickly as it will make life so much easier. At my boat club, we do these tests once a term and it's always the guys with the running background that triumph even if they aren't necessarily the best guys over an hour on the ergo.