That’s really nice that you have already started preparing for cross country running. The cross country running must be really fun as you have to run over a variety of surfaces – from dirt and grass to mud, sharp turns, short steep hills, long cantered sections, logs to jump, creeks to cross, bridges to negotiate…. I believe it’s much more difficult than running on just a flat surface.
You can refer this article which I believe is really interesting for crosscountry runner training and will tell you how to improve…
There’s,different training for speed and stamina and it depends on what type of distances you’re running over. If you’re lucky enough to be young then your body is still developing and your stamina will improve, but be carful not to overdo any one type of training interval or exercise as it can lead to injuries especially in a still developing physique. Try and keep a good mix of sports but don’t just stick to running.
The mental side is a huge part of distance running and the Kenyans are masters of pain management. They feel the same pain as other runners but they have well developed cultural techniques to just keep going! Try and do some pain management exercises. Try holding an ice cube and you’ll get to 30 seconds, but concentrate and breathe through it and you can hold it until it melts. Try it!