Long Distance Running
Long distance running is all about getting into a rhythm and keeping going at a pace. If you go a bit too fast, you'll blow up, if you start too slow it is very difficult to catch time up.
Most of the important work that you will do is based around improving your endurance and developing your aerobic system through increasing your VO2 max level and improving your running economy (the efficiency of your running technique over periods of time). However, strength and core stability should not be neglected as these are important for maintaining form during the full length of a race.