Enjoy getting raped when Disco gets his hands on you. There are numerous posts and even a sticky on run times. Try the search function or at least have a look through the run time sticky before jumping in with a new topic and you might get some helpful advice.
run a lot try to do 3 milers and get your overal time down to between 15 to 20 mins, once you cna do that you should be able to push out 8 min runs easy enough, slightly longer distances including some uphills will give you much better trainign value than running the required distance, personally back when i was training (ok so it was a long time ago) i alternated between 3, 5 and 8 miles doing both xcountry and roadwork, it gives you a better mix up and provides you with beter endurance, also try not to eat les than an hour before training as it can degrade your performance.
Find a mate who's a half decent runner and head down your nearest track. You sprint one lap (max effort) while he rests, then you rest while he does a lap, do it until you've done 6 laps each. That's 2400m/1.5miles. Helps get your recovery time down a treat, and as already said, 3milers are good and some longer distance runs to get some endurance.
make sure to wear proper trainers, not any of the trendy gear since its all shite and helps shagg out your knees, if you can get to one try beech running on shingle or soft sand its nasty but it reall does help to build up the endurance ratings